Adapt dynamic question difficulty to learner Elo

api/QuestionsApi.Tests/DynamicQuestionTests.cs

@@ -80,6 +80,71 @@ public sealed class DynamicQuestionTests
         Assert.Equal(first.Choices.Select(value => value.Id), regenerated.Choices.Select(value => value.Id));
     }
 
+    [Fact]
+    public void DifficultyPolicy_BlendsThenSpecializes_AndTargetsSixtyPercent()
+    {
+        Assert.Equal(1200, DynamicDifficultyPolicy.EffectiveAbility(1100, 1300, null));
+        var early = new DynamicObjectiveMastery { Elo = 1500, Attempts = 1 };
+        var established = new DynamicObjectiveMastery { Elo = 1500, Attempts = 10 };
+        Assert.Equal(1224, DynamicDifficultyPolicy.EffectiveAbility(1100, 1300, early));
+        Assert.Equal(1440, DynamicDifficultyPolicy.EffectiveAbility(1100, 1300, established));
+        Assert.Equal(1370, DynamicDifficultyPolicy.TargetFamilyElo(1440));
+    }
+
+    [Fact]
+    public void DifficultyPolicy_SelectsClosestNonrecentFamily()
+    {
+        var families = new List<DynamicCaseFamily>
+        {
+            new() { Id = "foundation", DifficultyTier = "foundation", NominalElo = 850 },
+            new() { Id = "standard", DifficultyTier = "standard", NominalElo = 1050 },
+            new() { Id = "advanced-a", DifficultyTier = "advanced", NominalElo = 1250 },
+            new() { Id = "advanced-b", DifficultyTier = "advanced", NominalElo = 1250 },
+            new() { Id = "expert", DifficultyTier = "expert", NominalElo = 1450 }
+        };
+        var selected = DynamicDifficultyPolicy.SelectFamily(
+            families, new Dictionary<string, DynamicFamilyRating>(), 1260,
+            new HashSet<string> { "advanced-a" }, 0);
+        Assert.Equal("advanced-b", selected.Id);
+    }
+
+    [Fact]
+    public void DifficultyPolicy_RatingsMoveInOppositeDirections()
+    {
+        Assert.True(DynamicDifficultyPolicy.LearnerDelta(1000, 1050, true, 0) > 0);
+        Assert.True(DynamicDifficultyPolicy.FamilyDelta(1000, 1050, true, 0) < 0);
+        Assert.True(DynamicDifficultyPolicy.LearnerDelta(1000, 1050, false, 0) < 0);
+        Assert.True(DynamicDifficultyPolicy.FamilyDelta(1000, 1050, false, 0) > 0);
+        Assert.Equal(600, DynamicDifficultyPolicy.Clamp(-100));
+        Assert.Equal(1800, DynamicDifficultyPolicy.Clamp(5000));
+    }
+
+    [Fact]
+    public void AdaptiveContent_ResolvesToFourCompleteTiers()
+    {
+        var options = new System.Text.Json.JsonSerializerOptions(System.Text.Json.JsonSerializerDefaults.Web)
+            { PropertyNameCaseInsensitive = true };
+        var root = Path.GetFullPath(Path.Combine(
+            AppContext.BaseDirectory, "..", "..", "..", "..", "..", "content", "dynamic_questions"));
+        var source = Directory.EnumerateFiles(root, "*.json")
+            .SelectMany(file => System.Text.Json.JsonSerializer.Deserialize<List<DynamicQuestionBlueprint>>(
+                File.ReadAllText(file), options) ?? [])
+            .ToList();
+        var adaptive = DynamicBlueprintResolver.ResolveAll(source)
+            .Where(value => value.QualityStandardVersion >= 3).ToList();
+
+        Assert.Equal(5, adaptive.Count);
+        Assert.All(adaptive, blueprint =>
+        {
+            Assert.Equal(8, blueprint.CaseFamilies.Count);
+            Assert.All(DynamicDifficultyPolicy.TierElos.Keys, tier =>
+                Assert.Equal(2, blueprint.CaseFamilies.Count(value => value.DifficultyTier == tier)));
+            Assert.All(blueprint.CaseFamilies, family =>
+                Assert.False(family.StemTemplate.EndsWith(family.LeadIn, StringComparison.Ordinal)));
+            Assert.Null(DynamicQuestionGenerator.Validate(blueprint));
+        });
+    }
+
     private static DynamicQuestionBlueprint Blueprint() => new()
     {
         ExternalId = "test",

api/QuestionsApi/Models/DynamicQuestionModels.cs

@@ -19,6 +19,7 @@ public sealed class DynamicQuestionBlueprint
     public int Difficulty { get; set; } = 3;
     public int QualityStandardVersion { get; set; } = 1;
     public string CorrectConceptId { get; set; } = "";
+    public int BaseBlueprintVersion { get; set; }
     public bool IsPublished { get; set; } = true;
     public string StemTemplate { get; set; } = "";
     public string LeadIn { get; set; } = "";
@@ -41,6 +42,9 @@ public sealed class DynamicQuestionBlueprint
 public sealed class DynamicCaseFamily
 {
     public string Id { get; set; } = "";
+    public string BaseFamilyId { get; set; } = "";
+    public string DifficultyTier { get; set; } = "standard";
+    public int NominalElo { get; set; } = 1050;
     public string StemTemplate { get; set; } = "";
     public string LeadIn { get; set; } = "";
     public Dictionary<string, DynamicVariableDefinition> Variables { get; set; } = [];
@@ -123,6 +127,9 @@ public sealed class DynamicGenerationClaims
     public string Nonce { get; set; } = "";
     public int GeneratorVersion { get; set; } = 1;
     public string CaseFamilyId { get; set; } = "";
+    public string DifficultyTier { get; set; } = "";
+    public int EffectiveAbilityElo { get; set; }
+    public int FamilyElo { get; set; }
     public DateTime ExpiresUtc { get; set; }
 }
 
@@ -204,6 +211,10 @@ public sealed class DynamicQuestionAttempt
     public string BlueprintExternalId { get; set; } = "";
     public int BlueprintVersion { get; set; }
     public string ObjectiveId { get; set; } = "";
+    public string CaseFamilyId { get; set; } = "";
+    public string DifficultyTier { get; set; } = "";
+    public int EffectiveAbilityElo { get; set; }
+    public int FamilyElo { get; set; }
     public string ChoiceId { get; set; } = "";
     public bool IsCorrect { get; set; }
     public bool IsSkip { get; set; }
@@ -224,6 +235,22 @@ public sealed class DynamicObjectiveMastery
     public DateTime LastSeenUtc { get; set; }
 }
 
+public sealed class DynamicFamilyRating
+{
+    [BsonId]
+    [BsonRepresentation(BsonType.ObjectId)]
+    public string? Id { get; set; }
+    public string BlueprintExternalId { get; set; } = "";
+    public int BlueprintVersion { get; set; }
+    public string CaseFamilyId { get; set; } = "";
+    public string DifficultyTier { get; set; } = "";
+    public int NominalElo { get; set; }
+    public int Elo { get; set; }
+    public int Attempts { get; set; }
+    public int Correct { get; set; }
+    public DateTime UpdatedUtc { get; set; } = DateTime.UtcNow;
+}
+
 public sealed class DynamicGenerationDescriptor
 {
     public string BlueprintExternalId { get; set; } = "";
@@ -231,4 +258,7 @@ public sealed class DynamicGenerationDescriptor
     public int GeneratorVersion { get; set; }
     public string Seed { get; set; } = "";
     public string CaseFamilyId { get; set; } = "";
+    public string DifficultyTier { get; set; } = "";
+    public int FamilyElo { get; set; }
+    public int EffectiveAbilityElo { get; set; }
 }

api/QuestionsApi/Services/DynamicBlueprintCommand.cs

@@ -22,6 +22,7 @@ public static class DynamicBlueprintCommand
         var blueprints = new List<DynamicQuestionBlueprint>();
         foreach (var file in Directory.EnumerateFiles(source, "*.json", SearchOption.AllDirectories))
             blueprints.AddRange(JsonSerializer.Deserialize<List<DynamicQuestionBlueprint>>(await File.ReadAllTextAsync(file), json) ?? []);
+        blueprints = DynamicBlueprintResolver.ResolveAll(blueprints);
 
         var generator = new DynamicQuestionGenerator();
         var generatedVariants = 0;

api/QuestionsApi/Services/DynamicBlueprintResolver.cs

@@ -0,0 +1,61 @@
+using QuestionsApi.Models;
+using System.Text.Json;
+
+namespace QuestionsApi.Services;
+
+public static class DynamicBlueprintResolver
+{
+    private static readonly JsonSerializerOptions Json = new(JsonSerializerDefaults.Web);
+
+    public static List<DynamicQuestionBlueprint> ResolveAll(IEnumerable<DynamicQuestionBlueprint> source)
+    {
+        var all = source.ToList();
+        var resolved = new List<DynamicQuestionBlueprint>();
+        foreach (var blueprint in all.OrderBy(value => value.Version))
+        {
+            if (blueprint.BaseBlueprintVersion <= 0)
+            {
+                resolved.Add(blueprint);
+                continue;
+            }
+            var baseBlueprint = resolved.FirstOrDefault(value =>
+                value.ExternalId == blueprint.ExternalId
+                && value.Version == blueprint.BaseBlueprintVersion)
+                ?? throw new InvalidDataException(
+                    $"{blueprint.ExternalId} v{blueprint.Version} base version {blueprint.BaseBlueprintVersion} not found");
+            var materialized = Clone(baseBlueprint);
+            materialized.Id = null;
+            materialized.Version = blueprint.Version;
+            materialized.BaseBlueprintVersion = blueprint.BaseBlueprintVersion;
+            materialized.QualityStandardVersion = blueprint.QualityStandardVersion;
+            materialized.IsPublished = blueprint.IsPublished;
+            materialized.CaseFamilies = blueprint.CaseFamilies.Select(overlay =>
+            {
+                var baseFamily = baseBlueprint.CaseFamilies.FirstOrDefault(value => value.Id == overlay.BaseFamilyId)
+                    ?? throw new InvalidDataException(
+                        $"{blueprint.ExternalId} v{blueprint.Version} base family {overlay.BaseFamilyId} not found");
+                var family = Clone(baseFamily);
+                family.Id = overlay.Id;
+                family.BaseFamilyId = overlay.BaseFamilyId;
+                family.DifficultyTier = overlay.DifficultyTier;
+                family.NominalElo = overlay.NominalElo;
+                if (!string.IsNullOrWhiteSpace(family.LeadIn)
+                    && family.StemTemplate.EndsWith(family.LeadIn, StringComparison.Ordinal))
+                    family.StemTemplate = family.StemTemplate[..^family.LeadIn.Length].TrimEnd();
+                if (!string.IsNullOrWhiteSpace(overlay.StemTemplate))
+                    family.StemTemplate = $"{family.StemTemplate} {overlay.StemTemplate}".Trim();
+                if (!string.IsNullOrWhiteSpace(overlay.LeadIn))
+                    family.LeadIn = overlay.LeadIn;
+                if (overlay.Distractors.Count > 0)
+                    family.Distractors = overlay.Distractors;
+                return family;
+            }).ToList();
+            resolved.Add(materialized);
+        }
+        return resolved;
+    }
+
+    private static T Clone<T>(T value) =>
+        JsonSerializer.Deserialize<T>(JsonSerializer.Serialize(value, Json), Json)
+        ?? throw new InvalidOperationException("Blueprint clone failed.");
+}

api/QuestionsApi/Services/DynamicDifficultyPolicy.cs

@@ -0,0 +1,69 @@
+using QuestionsApi.Models;
+
+namespace QuestionsApi.Services;
+
+public static class DynamicDifficultyPolicy
+{
+    public const int MinimumElo = 600;
+    public const int MaximumElo = 1800;
+    public const int TargetOffset = 70;
+    public static readonly IReadOnlyDictionary<string, int> TierElos =
+        new Dictionary<string, int>(StringComparer.Ordinal)
+        {
+            ["foundation"] = 850,
+            ["standard"] = 1050,
+            ["advanced"] = 1250,
+            ["expert"] = 1450
+        };
+
+    public static int EffectiveAbility(
+        int overallElo,
+        int categoryElo,
+        DynamicObjectiveMastery? objective)
+    {
+        var bankAbility = (int)Math.Round((overallElo + categoryElo) / 2.0);
+        if (objective is null || objective.Attempts <= 0)
+            return Clamp(bankAbility);
+        var objectiveWeight = Math.Min(0.8, objective.Attempts * 0.08);
+        return Clamp((int)Math.Round(bankAbility * (1.0 - objectiveWeight) + objective.Elo * objectiveWeight));
+    }
+
+    public static int TargetFamilyElo(int effectiveAbility) => Clamp(effectiveAbility - TargetOffset);
+
+    public static double ExpectedScore(int playerElo, int familyElo) =>
+        1.0 / (1.0 + Math.Pow(10, (familyElo - playerElo) / 400.0));
+
+    public static int LearnerDelta(int playerElo, int familyElo, bool correct, int attempts) =>
+        (int)Math.Round((attempts < 5 ? 40 : 24)
+            * ((correct ? 1.0 : 0.0) - ExpectedScore(playerElo, familyElo)));
+
+    public static int FamilyDelta(int playerElo, int familyElo, bool correct, int attempts) =>
+        (int)Math.Round((attempts < 20 ? 32 : 24)
+            * (ExpectedScore(playerElo, familyElo) - (correct ? 1.0 : 0.0)));
+
+    public static DynamicCaseFamily SelectFamily(
+        IReadOnlyList<DynamicCaseFamily> families,
+        IReadOnlyDictionary<string, DynamicFamilyRating> ratings,
+        int targetElo,
+        ISet<string> recentFamilyIds,
+        int tieBreaker)
+    {
+        if (families.Count == 0) throw new InvalidOperationException("No case families are available.");
+        var eligible = families.Where(value => !recentFamilyIds.Contains(value.Id)).ToList();
+        if (eligible.Count == 0) eligible = families.ToList();
+        var ranked = eligible
+            .Select(value => new
+            {
+                Family = value,
+                Elo = ratings.TryGetValue(value.Id, out var rating) ? rating.Elo : value.NominalElo
+            })
+            .OrderBy(value => Math.Abs(value.Elo - targetElo))
+            .ThenBy(value => value.Family.Id, StringComparer.Ordinal)
+            .ToList();
+        var bestDistance = Math.Abs(ranked[0].Elo - targetElo);
+        var tied = ranked.Where(value => Math.Abs(value.Elo - targetElo) == bestDistance).ToList();
+        return tied[Math.Abs(tieBreaker) % tied.Count].Family;
+    }
+
+    public static int Clamp(int elo) => Math.Clamp(elo, MinimumElo, MaximumElo);
+}

api/QuestionsApi/Services/DynamicQuestionGenerator.cs

@@ -11,9 +11,14 @@ public sealed class DynamicQuestionGenerator
     public const int CurrentVersion = 2;
     private static readonly Regex Placeholder = new(@"\{\{([a-zA-Z0-9_]+)\}\}", RegexOptions.Compiled);
 
-    public DynamicGeneratedQuestion Generate(DynamicQuestionBlueprint blueprint, string seed, string nonce, int generatorVersion = CurrentVersion)
+    public DynamicGeneratedQuestion Generate(
+        DynamicQuestionBlueprint blueprint,
+        string seed,
+        string nonce,
+        int generatorVersion = CurrentVersion,
+        string caseFamilyId = "")
         => blueprint.QualityStandardVersion >= 2
-            ? GenerateV2(blueprint, seed, nonce)
+            ? GenerateV2(blueprint, seed, nonce, caseFamilyId)
             : GenerateLegacy(blueprint, seed, nonce, generatorVersion);
 
     private DynamicGeneratedQuestion GenerateLegacy(DynamicQuestionBlueprint blueprint, string seed, string nonce, int generatorVersion)
@@ -117,13 +122,16 @@ public sealed class DynamicQuestionGenerator
         return new DynamicGeneratedQuestion { Question = question, Blueprint = blueprint };
     }
 
-    private DynamicGeneratedQuestion GenerateV2(DynamicQuestionBlueprint blueprint, string seed, string nonce)
+    private DynamicGeneratedQuestion GenerateV2(DynamicQuestionBlueprint blueprint, string seed, string nonce, string caseFamilyId)
     {
         if (blueprint.CaseFamilies.Count == 0)
             throw new InvalidOperationException("quality-standard-2 blueprints require case families");
         var draw = new DeterministicDraw($"{blueprint.ExternalId}|{blueprint.Version}|{CurrentVersion}|{seed}");
-        var family = blueprint.CaseFamilies.OrderBy(value => value.Id, StringComparer.Ordinal)
-            .ElementAt(draw.Next(blueprint.CaseFamilies.Count));
+        var orderedFamilies = blueprint.CaseFamilies.OrderBy(value => value.Id, StringComparer.Ordinal).ToList();
+        var family = string.IsNullOrWhiteSpace(caseFamilyId)
+            ? orderedFamilies[draw.Next(orderedFamilies.Count)]
+            : orderedFamilies.FirstOrDefault(value => value.Id == caseFamilyId)
+                ?? throw new InvalidOperationException($"case family {caseFamilyId} is unavailable");
         var values = new Dictionary<string, string>(StringComparer.Ordinal);
         var numbers = new Dictionary<string, double>(StringComparer.Ordinal);
         if (family.ValueBundles.Count > 0)
@@ -178,7 +186,14 @@ public sealed class DynamicQuestionGenerator
             Discipline = blueprint.Discipline,
             System = blueprint.System,
             PerformanceCategory = blueprint.PerformanceCategory,
-            Difficulty = blueprint.Difficulty,
+            Difficulty = family.DifficultyTier switch
+            {
+                "foundation" => 1,
+                "standard" => 2,
+                "advanced" => 4,
+                "expert" => 5,
+                _ => blueprint.Difficulty
+            },
             Labs = family.Labs.Select(lab => new QuestionLab
             {
                 Name = lab.Name,
@@ -327,6 +342,19 @@ public sealed class DynamicQuestionGenerator
         if (blueprint.References.Count == 0) return "at least one reference required";
         if (blueprint.CaseFamilies.Select(value => value.Id).Distinct(StringComparer.Ordinal).Count() != blueprint.CaseFamilies.Count)
             return "case family ids must be unique";
+        if (blueprint.QualityStandardVersion >= 3)
+        {
+            foreach (var tier in DynamicDifficultyPolicy.TierElos)
+            {
+                var tierFamilies = blueprint.CaseFamilies
+                    .Where(value => value.DifficultyTier == tier.Key).ToList();
+                if (tierFamilies.Count < 2) return $"at least two {tier.Key} case families required";
+                if (tierFamilies.Any(value => Math.Abs(value.NominalElo - tier.Value) > 100))
+                    return $"{tier.Key} nominal Elo must be within 100 points of {tier.Value}";
+            }
+            if (blueprint.CaseFamilies.Any(value => !DynamicDifficultyPolicy.TierElos.ContainsKey(value.DifficultyTier)))
+                return "difficultyTier must be foundation, standard, advanced, or expert";
+        }
         foreach (var family in blueprint.CaseFamilies)
         {
             if (string.IsNullOrWhiteSpace(family.Id)) return "case family id required";

api/QuestionsApi/Services/DynamicQuestionService.cs

@@ -8,15 +8,21 @@ public sealed class DynamicQuestionService
     private readonly DynamicQuestionStore _store;
     private readonly DynamicQuestionGenerator _generator;
     private readonly DynamicQuestionTokenService _tokens;
+    private readonly RatingStore _ratings;
+    private readonly ServiceMetrics _metrics;
 
     public DynamicQuestionService(
         DynamicQuestionStore store,
         DynamicQuestionGenerator generator,
-        DynamicQuestionTokenService tokens)
+        DynamicQuestionTokenService tokens,
+        RatingStore ratings,
+        ServiceMetrics metrics)
     {
         _store = store;
         _generator = generator;
         _tokens = tokens;
+        _ratings = ratings;
+        _metrics = metrics;
     }
 
     public Task<DynamicQuestionStatusResponse> StatusAsync(string userId) => _store.StatusAsync(userId);
@@ -53,6 +59,30 @@ public sealed class DynamicQuestionService
         var blueprint = selectedObjective
             .OrderByDescending(value => value.Version)
             .First();
+        var ratingProfile = await _ratings.GetProfileAsync(userId);
+        mastery.TryGetValue(blueprint.ObjectiveId, out var objectiveMastery);
+        var category = RatingCategory.Normalize(
+            blueprint.PerformanceCategory, blueprint.System, blueprint.Discipline);
+        var categoryElo = ratingProfile.CategoryElos.GetValueOrDefault(category, ratingProfile.OverallElo);
+        var effectiveAbility = DynamicDifficultyPolicy.EffectiveAbility(
+            ratingProfile.OverallElo, categoryElo, objectiveMastery);
+        var targetElo = DynamicDifficultyPolicy.TargetFamilyElo(effectiveAbility);
+        var familyRatings = await _store.FamilyRatingsAsync(blueprint);
+        var blueprintFamilyIds = blueprint.CaseFamilies.Select(value => value.Id).ToHashSet(StringComparer.Ordinal);
+        var recentForObjective = run.RecentCaseFamilyIds
+            .Where(blueprintFamilyIds.Contains)
+            .TakeLast(Math.Max(1, blueprint.CaseFamilies.Count / 4))
+            .ToHashSet(StringComparer.Ordinal);
+        var selectedFamily = DynamicDifficultyPolicy.SelectFamily(
+            blueprint.CaseFamilies,
+            familyRatings,
+            targetElo,
+            recentForObjective,
+            RandomNumberGenerator.GetInt32(int.MaxValue));
+        var selectedFamilyElo = familyRatings.TryGetValue(selectedFamily.Id, out var selectedRating)
+            ? selectedRating.Elo
+            : selectedFamily.NominalElo;
+        _metrics.DynamicSelected(selectedFamily.DifficultyTier, selectedFamilyElo - targetElo);
 
         var claims = new DynamicGenerationClaims
         {
@@ -63,20 +93,14 @@ public sealed class DynamicQuestionService
             Seed = Convert.ToHexString(RandomNumberGenerator.GetBytes(16)).ToLowerInvariant(),
             Nonce = Guid.NewGuid().ToString("N"),
             GeneratorVersion = DynamicQuestionGenerator.CurrentVersion,
+            CaseFamilyId = selectedFamily.Id,
+            DifficultyTier = selectedFamily.DifficultyTier,
+            EffectiveAbilityElo = effectiveAbility,
+            FamilyElo = selectedFamilyElo,
             ExpiresUtc = DateTime.UtcNow.AddDays(7)
         };
-        var generated = _generator.Generate(blueprint, claims.Seed, claims.Nonce, claims.GeneratorVersion);
-        var familyIds = blueprint.CaseFamilies.Select(value => value.Id).ToHashSet(StringComparer.Ordinal);
-        var recentForObjective = run.RecentCaseFamilyIds
-            .Where(familyIds.Contains)
-            .TakeLast(Math.Max(1, blueprint.CaseFamilies.Count - 1))
-            .ToHashSet(StringComparer.Ordinal);
-        for (var retry = 0; retry < 20 && recentForObjective.Contains(generated.CaseFamilyId); retry++)
-        {
-            claims.Seed = Convert.ToHexString(RandomNumberGenerator.GetBytes(16)).ToLowerInvariant();
-            generated = _generator.Generate(blueprint, claims.Seed, claims.Nonce);
-        }
-        claims.CaseFamilyId = generated.CaseFamilyId;
+        var generated = _generator.Generate(
+            blueprint, claims.Seed, claims.Nonce, claims.GeneratorVersion, claims.CaseFamilyId);
         run.SeenObjectiveIds.Add(blueprint.ObjectiveId);
         run.PreviousObjectiveId = blueprint.ObjectiveId;
         run.RecentCaseFamilyIds.Add(generated.CaseFamilyId);
@@ -84,7 +108,7 @@ public sealed class DynamicQuestionService
         run.ExpiresUtc = DateTime.UtcNow.AddDays(7);
         return new DynamicQuestionEnvelope
         {
-            Question = QuestionResponse.FromModel(generated.Question),
+            Question = QuestionResponse.FromModel(generated.Question, questionElo: selectedFamilyElo),
             ObjectiveId = blueprint.ObjectiveId,
             ObjectiveTitle = blueprint.Title,
             GenerationToken = _tokens.SignGeneration(claims),
@@ -109,7 +133,8 @@ public sealed class DynamicQuestionService
             throw new InvalidOperationException("This generated question version is no longer supported.");
         var blueprint = await _store.GetAsync(claims.BlueprintExternalId, claims.BlueprintVersion)
             ?? throw new KeyNotFoundException("The question blueprint is no longer available.");
-        var generated = _generator.Generate(blueprint, claims.Seed, claims.Nonce, claims.GeneratorVersion);
+        var generated = _generator.Generate(
+            blueprint, claims.Seed, claims.Nonce, claims.GeneratorVersion, claims.CaseFamilyId);
         if (!string.IsNullOrWhiteSpace(claims.CaseFamilyId)
             && claims.CaseFamilyId != generated.CaseFamilyId)
             throw new InvalidOperationException("Generated case family does not match its signed descriptor.");

api/QuestionsApi/Services/DynamicQuestionStore.cs

@@ -9,12 +9,16 @@ public sealed class DynamicQuestionStore
     private readonly IMongoCollection<DynamicQuestionBlueprint> _blueprints;
     private readonly IMongoCollection<DynamicQuestionAttempt> _attempts;
     private readonly IMongoCollection<DynamicObjectiveMastery> _mastery;
+    private readonly IMongoCollection<DynamicFamilyRating> _familyRatings;
+    private readonly ServiceMetrics? _metrics;
 
-    public DynamicQuestionStore(MongoDatabaseProvider mongo)
+    public DynamicQuestionStore(MongoDatabaseProvider mongo, ServiceMetrics? metrics = null)
     {
+        _metrics = metrics;
         _blueprints = mongo.Database.GetCollection<DynamicQuestionBlueprint>("DynamicQuestionBlueprints");
         _attempts = mongo.Database.GetCollection<DynamicQuestionAttempt>("DynamicQuestionAttempts");
         _mastery = mongo.Database.GetCollection<DynamicObjectiveMastery>("DynamicObjectiveMastery");
+        _familyRatings = mongo.Database.GetCollection<DynamicFamilyRating>("DynamicFamilyRatings");
         _blueprints.Indexes.CreateOne(new CreateIndexModel<DynamicQuestionBlueprint>(
             Builders<DynamicQuestionBlueprint>.IndexKeys.Ascending(value => value.ExternalId).Ascending(value => value.Version),
             new CreateIndexOptions { Unique = true }));
@@ -24,6 +28,12 @@ public sealed class DynamicQuestionStore
         _mastery.Indexes.CreateOne(new CreateIndexModel<DynamicObjectiveMastery>(
             Builders<DynamicObjectiveMastery>.IndexKeys.Ascending(value => value.UserId).Ascending(value => value.ObjectiveId),
             new CreateIndexOptions { Unique = true }));
+        _familyRatings.Indexes.CreateOne(new CreateIndexModel<DynamicFamilyRating>(
+            Builders<DynamicFamilyRating>.IndexKeys
+                .Ascending(value => value.BlueprintExternalId)
+                .Ascending(value => value.BlueprintVersion)
+                .Ascending(value => value.CaseFamilyId),
+            new CreateIndexOptions { Unique = true }));
     }
 
     public async Task<List<DynamicQuestionBlueprint>> PublishedAsync() =>
@@ -36,6 +46,14 @@ public sealed class DynamicQuestionStore
         (await _mastery.Find(value => value.UserId == userId).ToListAsync())
         .ToDictionary(value => value.ObjectiveId, StringComparer.Ordinal);
 
+    public async Task<Dictionary<string, DynamicFamilyRating>> FamilyRatingsAsync(DynamicQuestionBlueprint blueprint)
+    {
+        var ratings = await _familyRatings.Find(value =>
+            value.BlueprintExternalId == blueprint.ExternalId
+            && value.BlueprintVersion == blueprint.Version).ToListAsync();
+        return ratings.ToDictionary(value => value.CaseFamilyId, StringComparer.Ordinal);
+    }
+
     public async Task<DynamicAttemptResponse> RecordAsync(
         DynamicGenerationClaims claims,
         DynamicGeneratedQuestion generated,
@@ -49,6 +67,10 @@ public sealed class DynamicQuestionStore
             BlueprintExternalId = claims.BlueprintExternalId,
             BlueprintVersion = claims.BlueprintVersion,
             ObjectiveId = claims.ObjectiveId,
+            CaseFamilyId = claims.CaseFamilyId,
+            DifficultyTier = claims.DifficultyTier,
+            EffectiveAbilityElo = claims.EffectiveAbilityElo,
+            FamilyElo = claims.FamilyElo,
             ChoiceId = request.ChoiceId,
             IsCorrect = isCorrect,
             IsSkip = request.IsSkip,
@@ -68,25 +90,33 @@ public sealed class DynamicQuestionStore
                 ObjectiveElo = existingMastery?.Elo ?? 1000
             };
         }
+        _metrics?.DynamicAttempt(claims.DifficultyTier, isCorrect);
 
-        var current = await _mastery.Find(value => value.UserId == claims.UserId && value.ObjectiveId == claims.ObjectiveId).FirstOrDefaultAsync();
-        var oldElo = current?.Elo ?? 1000;
-        var objectiveDifficulty = 800 + Math.Clamp(generated.Blueprint.Difficulty, 1, 5) * 100;
-        var expected = 1.0 / (1.0 + Math.Pow(10, (objectiveDifficulty - oldElo) / 400.0));
-        var k = (current?.Attempts ?? 0) < 5 ? 40 : 24;
-        var delta = (int)Math.Round(k * ((isCorrect ? 1.0 : 0.0) - expected));
+        await EnsureMasteryAsync(claims.UserId, claims.ObjectiveId);
+        var current = await _mastery.Find(value => value.UserId == claims.UserId && value.ObjectiveId == claims.ObjectiveId).FirstAsync()
+            ?? throw new InvalidOperationException("Dynamic objective mastery could not be initialized.");
+        var oldElo = current.Elo;
+        var familyElo = claims.FamilyElo > 0
+            ? claims.FamilyElo
+            : 800 + Math.Clamp(generated.Blueprint.Difficulty, 1, 5) * 100;
+        var delta = DynamicDifficultyPolicy.LearnerDelta(oldElo, familyElo, isCorrect, current.Attempts);
         var now = DateTime.UtcNow;
         var update = Builders<DynamicObjectiveMastery>.Update
-            .SetOnInsert(value => value.UserId, claims.UserId)
-            .SetOnInsert(value => value.ObjectiveId, claims.ObjectiveId)
-            .Set(value => value.Elo, oldElo + delta)
+            .Inc(value => value.Elo, delta)
             .Inc(value => value.Attempts, 1)
             .Inc(value => value.Correct, isCorrect ? 1 : 0)
             .Set(value => value.LastSeenUtc, now);
         var updated = await _mastery.FindOneAndUpdateAsync(
             value => value.UserId == claims.UserId && value.ObjectiveId == claims.ObjectiveId,
             update,
-            new FindOneAndUpdateOptions<DynamicObjectiveMastery> { IsUpsert = true, ReturnDocument = ReturnDocument.After });
+            new FindOneAndUpdateOptions<DynamicObjectiveMastery> { ReturnDocument = ReturnDocument.After });
+        await _mastery.UpdateOneAsync(
+            value => value.UserId == claims.UserId && value.ObjectiveId == claims.ObjectiveId,
+            Builders<DynamicObjectiveMastery>.Update
+                .Max(value => value.Elo, DynamicDifficultyPolicy.MinimumElo)
+                .Min(value => value.Elo, DynamicDifficultyPolicy.MaximumElo));
+        if (!string.IsNullOrWhiteSpace(claims.CaseFamilyId))
+            await UpdateFamilyRatingAsync(claims, generated, isCorrect);
         return new DynamicAttemptResponse
         {
             Inserted = true,
@@ -98,6 +128,70 @@ public sealed class DynamicQuestionStore
         };
     }
 
+    private async Task EnsureMasteryAsync(string userId, string objectiveId)
+    {
+        try
+        {
+            await _mastery.UpdateOneAsync(
+                value => value.UserId == userId && value.ObjectiveId == objectiveId,
+                Builders<DynamicObjectiveMastery>.Update
+                    .SetOnInsert(value => value.UserId, userId)
+                    .SetOnInsert(value => value.ObjectiveId, objectiveId)
+                    .SetOnInsert(value => value.Elo, 1000)
+                    .SetOnInsert(value => value.Attempts, 0)
+                    .SetOnInsert(value => value.Correct, 0),
+                new UpdateOptions { IsUpsert = true });
+        }
+        catch (MongoWriteException exception) when (exception.WriteError.Category == ServerErrorCategory.DuplicateKey) { }
+    }
+
+    private async Task UpdateFamilyRatingAsync(
+        DynamicGenerationClaims claims,
+        DynamicGeneratedQuestion generated,
+        bool isCorrect)
+    {
+        var family = generated.Blueprint.CaseFamilies.First(value => value.Id == claims.CaseFamilyId);
+        try
+        {
+            await _familyRatings.UpdateOneAsync(
+                value => value.BlueprintExternalId == claims.BlueprintExternalId
+                    && value.BlueprintVersion == claims.BlueprintVersion
+                    && value.CaseFamilyId == claims.CaseFamilyId,
+                Builders<DynamicFamilyRating>.Update
+                    .SetOnInsert(value => value.BlueprintExternalId, claims.BlueprintExternalId)
+                    .SetOnInsert(value => value.BlueprintVersion, claims.BlueprintVersion)
+                    .SetOnInsert(value => value.CaseFamilyId, claims.CaseFamilyId)
+                    .SetOnInsert(value => value.DifficultyTier, family.DifficultyTier)
+                    .SetOnInsert(value => value.NominalElo, family.NominalElo)
+                    .SetOnInsert(value => value.Elo, family.NominalElo)
+                    .SetOnInsert(value => value.Attempts, 0)
+                    .SetOnInsert(value => value.Correct, 0),
+                new UpdateOptions { IsUpsert = true });
+        }
+        catch (MongoWriteException exception) when (exception.WriteError.Category == ServerErrorCategory.DuplicateKey) { }
+        var current = await _familyRatings.Find(value =>
+            value.BlueprintExternalId == claims.BlueprintExternalId
+            && value.BlueprintVersion == claims.BlueprintVersion
+            && value.CaseFamilyId == claims.CaseFamilyId).FirstAsync();
+        var delta = DynamicDifficultyPolicy.FamilyDelta(
+            claims.EffectiveAbilityElo > 0 ? claims.EffectiveAbilityElo : 1000,
+            claims.FamilyElo > 0 ? claims.FamilyElo : current.Elo,
+            isCorrect,
+            current.Attempts);
+        await _familyRatings.UpdateOneAsync(
+            value => value.Id == current.Id,
+            Builders<DynamicFamilyRating>.Update
+                .Inc(value => value.Elo, delta)
+                .Inc(value => value.Attempts, 1)
+                .Inc(value => value.Correct, isCorrect ? 1 : 0)
+                .Set(value => value.UpdatedUtc, DateTime.UtcNow));
+        await _familyRatings.UpdateOneAsync(
+            value => value.Id == current.Id,
+            Builders<DynamicFamilyRating>.Update
+                .Max(value => value.Elo, DynamicDifficultyPolicy.MinimumElo)
+                .Min(value => value.Elo, DynamicDifficultyPolicy.MaximumElo));
+    }
+
     public async Task<DynamicQuestionStatusResponse> StatusAsync(string userId)
     {
         var objectiveCount = (await PublishedAsync()).Select(value => value.ObjectiveId).Distinct().Count();

api/QuestionsApi/Services/DynamicReviewExportCommand.cs

@@ -26,6 +26,7 @@ public static class DynamicReviewExportCommand
         foreach (var file in Directory.EnumerateFiles(source, "*.json", SearchOption.AllDirectories))
             blueprints.AddRange(JsonSerializer.Deserialize<List<DynamicQuestionBlueprint>>(
                 await File.ReadAllTextAsync(file), jsonOptions) ?? []);
+        blueprints = DynamicBlueprintResolver.ResolveAll(blueprints);
         blueprints = blueprints.Where(value => value.IsPublished && value.QualityStandardVersion >= 2).ToList();
 
         var configuration = new ConfigurationBuilder()

api/QuestionsApi/Services/QuestionReportStore.cs

@@ -100,7 +100,10 @@ public class QuestionReportStore
                 BlueprintVersion = claims.BlueprintVersion,
                 GeneratorVersion = claims.GeneratorVersion,
                 Seed = claims.Seed,
-                CaseFamilyId = claims.CaseFamilyId
+                CaseFamilyId = claims.CaseFamilyId,
+                DifficultyTier = claims.DifficultyTier,
+                FamilyElo = claims.FamilyElo,
+                EffectiveAbilityElo = claims.EffectiveAbilityElo
             },
             CreatedUtc = now,
             UpdatedUtc = now

api/QuestionsApi/Services/ServiceMetrics.cs

@@ -13,6 +13,10 @@ public sealed class ServiceMetrics
     private long _httpRequests;
     private long _httpDurationMicroseconds;
     private long _answerStatisticsBackfillComplete;
+    private readonly System.Collections.Concurrent.ConcurrentDictionary<string, long> _dynamicSelections = new();
+    private readonly System.Collections.Concurrent.ConcurrentDictionary<string, long> _dynamicAttempts = new();
+    private readonly System.Collections.Concurrent.ConcurrentDictionary<string, long> _dynamicCorrect = new();
+    private long _dynamicTargetGapTotal;
 
     public void AttemptCreated() => Interlocked.Increment(ref _attemptsCreated);
     public void AttemptDuplicate() => Interlocked.Increment(ref _attemptDuplicates);
@@ -29,6 +33,16 @@ public sealed class ServiceMetrics
         Interlocked.Increment(ref _httpRequests);
         Interlocked.Add(ref _httpDurationMicroseconds, (long)(duration.TotalMilliseconds * 1000));
     }
+    public void DynamicSelected(string tier, int targetGap)
+    {
+        _dynamicSelections.AddOrUpdate(tier, 1, (_, value) => value + 1);
+        Interlocked.Add(ref _dynamicTargetGapTotal, Math.Abs(targetGap));
+    }
+    public void DynamicAttempt(string tier, bool correct)
+    {
+        _dynamicAttempts.AddOrUpdate(tier, 1, (_, value) => value + 1);
+        if (correct) _dynamicCorrect.AddOrUpdate(tier, 1, (_, value) => value + 1);
+    }
 
     public string RenderPrometheus()
     {
@@ -39,6 +53,16 @@ public sealed class ServiceMetrics
         AppendCounter(output, "step3_rating_failures_total", Interlocked.Read(ref _ratingFailures));
         AppendCounter(output, "step3_answer_reconciliations_total", Interlocked.Read(ref _reconciliations));
         AppendCounter(output, "step3_http_requests_total", Interlocked.Read(ref _httpRequests));
+        output.AppendLine("# TYPE step3_dynamic_selections_total counter");
+        output.AppendLine("# TYPE step3_dynamic_attempts_total counter");
+        output.AppendLine("# TYPE step3_dynamic_correct_total counter");
+        foreach (var tier in _dynamicSelections.Keys.Order())
+        {
+            AppendLabeledSample(output, "step3_dynamic_selections_total", tier, _dynamicSelections.GetValueOrDefault(tier));
+            AppendLabeledSample(output, "step3_dynamic_attempts_total", tier, _dynamicAttempts.GetValueOrDefault(tier));
+            AppendLabeledSample(output, "step3_dynamic_correct_total", tier, _dynamicCorrect.GetValueOrDefault(tier));
+        }
+        AppendCounter(output, "step3_dynamic_target_gap_points_total", Interlocked.Read(ref _dynamicTargetGapTotal));
         output.AppendLine("# TYPE step3_http_request_duration_seconds summary");
         output.Append("step3_http_request_duration_seconds_count ")
             .Append(Interlocked.Read(ref _httpRequests))
@@ -62,4 +86,9 @@ public sealed class ServiceMetrics
         output.Append("# TYPE ").Append(name).AppendLine(" counter");
         output.Append(name).Append(' ').Append(value).AppendLine();
     }
+
+    private static void AppendLabeledSample(StringBuilder output, string name, string tier, long value)
+    {
+        output.Append(name).Append("{tier=\"").Append(tier.Replace("\"", "")).Append("\"} ").Append(value).AppendLine();
+    }
 }

content/dynamic_questions/adaptive-v3.json

@@ -0,0 +1,72 @@
+[
+  {
+    "externalId":"dyn-gold-dka","version":3,"baseBlueprintVersion":2,
+    "qualityStandardVersion":3,"isPublished":true,
+    "caseFamilies":[
+      {"id":"dka-fnd-infection","baseFamilyId":"dka-infection","difficultyTier":"foundation","nominalElo":850,"stemTemplate":"The combination of hyperglycemia, ketonemia, and an anion-gap metabolic acidosis confirms diabetic ketoacidosis."},
+      {"id":"dka-fnd-new","baseFamilyId":"dka-new-onset","difficultyTier":"foundation","nominalElo":850,"stemTemplate":"The patient is clinically volume depleted, and there is no evidence of heart or kidney failure."},
+      {"id":"dka-std-pump","baseFamilyId":"dka-pump-failure","difficultyTier":"standard","nominalElo":1050,"stemTemplate":"The emergency team prepares simultaneous cardiac monitoring and repeat electrolyte measurements."},
+      {"id":"dka-std-infection","baseFamilyId":"dka-infection","difficultyTier":"standard","nominalElo":1050,"stemTemplate":"The urinary infection will require treatment, but the team must first sequence the metabolic resuscitation correctly."},
+      {"id":"dka-adv-new","baseFamilyId":"dka-new-onset","difficultyTier":"advanced","nominalElo":1250,"stemTemplate":"Although the measured serum potassium is not low, the patient has had substantial urinary potassium losses and has not yet received insulin."},
+      {"id":"dka-adv-pump","baseFamilyId":"dka-pump-failure","difficultyTier":"advanced","nominalElo":1250,"stemTemplate":"A family member asks whether reconnecting the pump alone will reverse the acute physiology."},
+      {"id":"dka-exp-infection","baseFamilyId":"dka-infection","difficultyTier":"expert","nominalElo":1450,"stemTemplate":"The patient received one antibiotic dose at urgent care; this does not explain the persistent shock physiology or alter the immediate metabolic priority."},
+      {"id":"dka-exp-pump","baseFamilyId":"dka-pump-failure","difficultyTier":"expert","nominalElo":1450,"stemTemplate":"Point-of-care ultrasound shows a small collapsible inferior vena cava and preserved left ventricular systolic function."}
+    ]
+  },
+  {
+    "externalId":"dyn-gold-af","version":3,"baseBlueprintVersion":2,
+    "qualityStandardVersion":3,"isPublished":true,
+    "caseFamilies":[
+      {"id":"af-fnd-sepsis","baseFamilyId":"af-sepsis","difficultyTier":"foundation","nominalElo":850,"stemTemplate":"The hypotension and confusion began with the rapid rhythm and are attributed to the tachyarrhythmia."},
+      {"id":"af-fnd-edema","baseFamilyId":"af-pulmonary-edema","difficultyTier":"foundation","nominalElo":850,"stemTemplate":"The patient has a pulse but has acute pulmonary edema and shock caused by the rapid rhythm."},
+      {"id":"af-std-ischemia","baseFamilyId":"af-ischemia","difficultyTier":"standard","nominalElo":1050,"stemTemplate":"The exact duration of atrial fibrillation is unknown."},
+      {"id":"af-std-sepsis","baseFamilyId":"af-sepsis","difficultyTier":"standard","nominalElo":1050,"stemTemplate":"Antibiotics and source control are underway, but perfusion continues to deteriorate as the ventricular rate rises."},
+      {"id":"af-adv-edema","baseFamilyId":"af-pulmonary-edema","difficultyTier":"advanced","nominalElo":1250,"stemTemplate":"The patient took the usual beta blocker this morning, and additional atrioventricular nodal blockade could worsen the low-output state."},
+      {"id":"af-adv-ischemia","baseFamilyId":"af-ischemia","difficultyTier":"advanced","nominalElo":1250,"stemTemplate":"A postoperative hemoglobin measurement is mildly decreased but stable and does not account for the abrupt hemodynamic change."},
+      {"id":"af-exp-sepsis","baseFamilyId":"af-sepsis","difficultyTier":"expert","nominalElo":1450,"stemTemplate":"A prior ECG showed sinus rhythm with a normal PR interval; the current tracing has no pre-excitation and the instability persists after a cautious fluid challenge."},
+      {"id":"af-exp-ischemia","baseFamilyId":"af-ischemia","difficultyTier":"expert","nominalElo":1450,"stemTemplate":"Bedside echocardiography shows no pericardial effusion or right ventricular dilation, narrowing the cause of shock to the rapid atrial arrhythmia."}
+    ]
+  },
+  {
+    "externalId":"dyn-gold-pyelo-pregnancy","version":3,"baseBlueprintVersion":2,
+    "qualityStandardVersion":3,"isPublished":true,
+    "caseFamilies":[
+      {"id":"pyelo-fnd-classic","baseFamilyId":"pyelo-classic","difficultyTier":"foundation","nominalElo":850,"stemTemplate":"The fever and costovertebral-angle tenderness distinguish this upper urinary tract infection from uncomplicated cystitis."},
+      {"id":"pyelo-fnd-recurrent","baseFamilyId":"pyelo-recurrent","difficultyTier":"foundation","nominalElo":850,"stemTemplate":"There is no drug allergy, and renal function is normal."},
+      {"id":"pyelo-std-systemic","baseFamilyId":"pyelo-systemic","difficultyTier":"standard","nominalElo":1050,"stemTemplate":"There is no evidence of obstructing nephrolithiasis on bedside assessment."},
+      {"id":"pyelo-std-classic","baseFamilyId":"pyelo-classic","difficultyTier":"standard","nominalElo":1050,"stemTemplate":"The patient can take oral medication but remains febrile and systemically ill."},
+      {"id":"pyelo-adv-recurrent","baseFamilyId":"pyelo-recurrent","difficultyTier":"advanced","nominalElo":1250,"stemTemplate":"The earlier urine isolate was susceptible to nitrofurantoin, but susceptibility does not overcome inadequate renal parenchymal penetration."},
+      {"id":"pyelo-adv-systemic","baseFamilyId":"pyelo-systemic","difficultyTier":"advanced","nominalElo":1250,"stemTemplate":"Mild uterine irritability resolves with hydration, and there is no indication for delivery."},
+      {"id":"pyelo-exp-classic","baseFamilyId":"pyelo-classic","difficultyTier":"expert","nominalElo":1450,"stemTemplate":"A preliminary culture reports a gram-negative rod; definitive susceptibilities will not be available until tomorrow."},
+      {"id":"pyelo-exp-systemic","baseFamilyId":"pyelo-systemic","difficultyTier":"expert","nominalElo":1450,"stemTemplate":"The lactate and respiratory rate raise concern for evolving maternal sepsis, making disposition as important as antibiotic spectrum."}
+    ]
+  },
+  {
+    "externalId":"dyn-gold-sah","version":3,"baseBlueprintVersion":2,
+    "qualityStandardVersion":3,"isPublished":true,
+    "caseFamilies":[
+      {"id":"sah-fnd-exertion","baseFamilyId":"sah-exertion","difficultyTier":"foundation","nominalElo":850,"stemTemplate":"The sudden maximal-at-onset headache and meningismus are classic warning features for subarachnoid hemorrhage."},
+      {"id":"sah-fnd-sentinel","baseFamilyId":"sah-sentinel","difficultyTier":"foundation","nominalElo":850,"stemTemplate":"This is a first thunderclap headache, not a recurrence of a previously evaluated migraine syndrome."},
+      {"id":"sah-std-focal","baseFamilyId":"sah-focal","difficultyTier":"standard","nominalElo":1050,"stemTemplate":"The patient is stable enough for immediate diagnostic imaging."},
+      {"id":"sah-std-exertion","baseFamilyId":"sah-exertion","difficultyTier":"standard","nominalElo":1050,"stemTemplate":"The absence of persistent focal weakness does not reduce the urgency of excluding hemorrhage."},
+      {"id":"sah-adv-sentinel","baseFamilyId":"sah-sentinel","difficultyTier":"advanced","nominalElo":1250,"stemTemplate":"The presentation occurred recently enough that the initial imaging strategy has high diagnostic yield, but a negative result must still be interpreted in clinical context."},
+      {"id":"sah-adv-focal","baseFamilyId":"sah-focal","difficultyTier":"advanced","nominalElo":1250,"stemTemplate":"The partial third-nerve finding raises concern for an aneurysmal source but does not replace the initial study for acute blood."},
+      {"id":"sah-exp-exertion","baseFamilyId":"sah-exertion","difficultyTier":"expert","nominalElo":1450,"stemTemplate":"A nonfocal examination and transient improvement after analgesia are potentially misleading and should not alter the first diagnostic step."},
+      {"id":"sah-exp-sentinel","baseFamilyId":"sah-sentinel","difficultyTier":"expert","nominalElo":1450,"stemTemplate":"Family history increases pretest probability, while the choice between subsequent lumbar puncture and angiographic evaluation depends on the result and timing of the initial study."}
+    ]
+  },
+  {
+    "externalId":"dyn-gold-arr","version":3,"baseBlueprintVersion":2,
+    "qualityStandardVersion":3,"isPublished":true,
+    "caseFamilies":[
+      {"id":"arr-fnd-cardio","baseFamilyId":"arr-cardiovascular","difficultyTier":"foundation","nominalElo":850,"stemTemplate":"Calculate the arithmetic difference between the two event rates rather than a relative measure."},
+      {"id":"arr-fnd-infection","baseFamilyId":"arr-infection","difficultyTier":"foundation","nominalElo":850,"stemTemplate":"The requested measure should be reported in percentage points."},
+      {"id":"arr-std-readmit","baseFamilyId":"arr-readmission","difficultyTier":"standard","nominalElo":1050,"stemTemplate":"Do not convert the result to number needed to treat unless specifically asked."},
+      {"id":"arr-std-cardio","baseFamilyId":"arr-cardiovascular","difficultyTier":"standard","nominalElo":1050,"stemTemplate":"The trial reports sufficient data to calculate absolute and relative effects directly."},
+      {"id":"arr-adv-infection","baseFamilyId":"arr-infection","difficultyTier":"advanced","nominalElo":1250,"stemTemplate":"A secondary table emphasizes a large relative reduction, but the question asks for the absolute treatment effect."},
+      {"id":"arr-adv-readmit","baseFamilyId":"arr-readmission","difficultyTier":"advanced","nominalElo":1250,"stemTemplate":"The intervention has similar follow-up completeness in both groups, so no adjustment for attrition is needed."},
+      {"id":"arr-exp-cardio","baseFamilyId":"arr-cardiovascular","difficultyTier":"expert","nominalElo":1450,"stemTemplate":"The authors additionally report an adjusted hazard ratio; that time-to-event estimate is not needed for this requested absolute measure."},
+      {"id":"arr-exp-readmit","baseFamilyId":"arr-readmission","difficultyTier":"expert","nominalElo":1450,"stemTemplate":"Cost-effectiveness and relative-risk results are presented as distractors, but neither changes the calculation from the observed event proportions."}
+    ]
+  }
+]

docs/dynamic-question-quality.md

@@ -3,6 +3,14 @@
 Quality-standard-2 blueprints are eligible for learner runs. Older blueprints
 remain stored only so signed questions and reports can be regenerated.
 
+Quality-standard-3 blueprints add Elo-adaptive difficulty. Each active objective
+must provide at least two families at every tier: foundation (850), standard
+(1050), advanced (1250), and expert (1450). The service targets an item about 70
+Elo below effective learner ability, approximately 60% expected correctness.
+Effective ability begins as an equal blend of overall and category question-bank
+Elo, then shifts toward dynamic objective Elo up to an 80% objective weight after
+10 attempts. Aggregate outcomes calibrate each case family's Elo over time.
+
 ## Content requirements
 
 - At least three curated case families per objective.