diff --git a/app/lib/dartdoc/dartdoc_runner.dart b/app/lib/dartdoc/dartdoc_runner.dart
index 9433a8d538..d299c8f5bf 100644
--- a/app/lib/dartdoc/dartdoc_runner.dart
+++ b/app/lib/dartdoc/dartdoc_runner.dart
@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
+import 'dart:convert' as convert;
 import 'dart:io';
 
 import 'package:logging/logging.dart';
@@ -26,6 +27,7 @@ import '../shared/versions.dart' as versions;
 import 'backend.dart';
 import 'customization.dart';
 import 'models.dart';
+import 'pub_dartdoc_data.dart';
 
 final Logger _logger = new Logger('pub.dartdoc.runner');
 final Uuid _uuid = new Uuid();
@@ -34,9 +36,14 @@ const statusFilePath = 'status.json';
 const _archiveFilePath = 'package.tar.gz';
 const _buildLogFilePath = 'log.txt';
 const _packageTimeout = const Duration(minutes: 10);
+const _pubDataFileName = 'pub-data.json';
 const _sdkTimeout = const Duration(minutes: 20);
 final Duration _twoYears = const Duration(days: 2 * 365);
 
+// We'll emit a suggestion and apply score penalty only if the coverage is below
+// this value.
+const _coverageEmitThreshold = 0.1;
+
 final _pkgPubDartdocDir =
     Platform.script.resolve('../../pkg/pub_dartdoc').toFilePath();
 
@@ -73,7 +80,7 @@ class DartdocJobProcessor extends JobProcessor {
         timeout: _sdkTimeout,
       );
 
-      final pubDataFile = new File(p.join(outputDir, 'pub-data.json'));
+      final pubDataFile = new File(p.join(outputDir, _pubDataFileName));
       final hasPubData = await pubDataFile.exists();
       final isOk = pr.exitCode == 0 && hasPubData;
       if (!isOk) {
@@ -124,7 +131,8 @@ class DartdocJobProcessor extends JobProcessor {
     bool hasContent = false;
 
     String reportStatus = ReportStatus.failed;
-    final suggestions = <Suggestion>[];
+    final healthSuggestions = <Suggestion>[];
+    final maintenanceSuggestions = <Suggestion>[];
     try {
       final pkgDir = await downloadPackage(job.packageName, job.packageVersion);
       if (pkgDir == null) {
@@ -197,17 +205,52 @@ class DartdocJobProcessor extends JobProcessor {
       await toolEnvRef.release();
     }
 
-    if (!hasContent) {
-      suggestions.add(getDartdocRunFailedSuggestion());
+    double coverageScore = 0.0;
+    final dartdocData = await _loadPubDartdocData(outputDir);
+    if (hasContent && dartdocData != null) {
+      final total = dartdocData.apiElements.length;
+      final documented = dartdocData.apiElements
+          .where((elem) =>
+              elem.documentation != null &&
+              elem.documentation.isNotEmpty &&
+              elem.documentation.trim().length >= 5)
+          .length;
+      if (total == documented) {
+        // this also handles total == 0
+        coverageScore = 1.0;
+      } else {
+        coverageScore = documented / total;
+      }
+
+      if (coverageScore < _coverageEmitThreshold) {
+        final level = coverageScore < 0.2
+            ? SuggestionLevel.warning
+            : SuggestionLevel.hint;
+        final undocumented = total - documented;
+        healthSuggestions.add(
+          new Suggestion(
+              'dartdoc.coverage', // TODO: extract as const in pana
+              level,
+              'Document public APIs',
+              '$undocumented out of $total API elements (library, class, field '
+              'or method) have no adequate dartdoc content. Good documentation '
+              'improves code readability and discoverability through search.',
+              score: (1.0 - coverageScore) * 10.0),
+        );
+      }
+    } else {
+      maintenanceSuggestions.add(getDartdocRunFailedSuggestion());
     }
-    // TODO: calculate coverage score
     await scoreCardBackend.updateReport(
         job.packageName,
         job.packageVersion,
         new DartdocReport(
           reportStatus: reportStatus,
-          coverageScore: hasContent ? 1.0 : 0.0,
-          suggestions: suggestions.isEmpty ? null : suggestions,
+          coverageScore: coverageScore,
+          healthSuggestions:
+              healthSuggestions.isEmpty ? null : healthSuggestions,
+          maintenanceSuggestions:
+              maintenanceSuggestions.isEmpty ? null : maintenanceSuggestions,
         ));
     await scoreCardBackend.updateScoreCard(job.packageName, job.packageVersion);
 
@@ -381,4 +424,19 @@ class DartdocJobProcessor extends JobProcessor {
     await tmpTar.rename(p.join(outputDir, _archiveFilePath));
     _appendLog(logFileOutput, pr);
   }
+
+  Future<PubDartdocData> _loadPubDartdocData(String outputDir) async {
+    final file = new File(p.join(outputDir, _pubDataFileName));
+    if (!file.existsSync()) {
+      return null;
+    }
+    try {
+      final content = await file.readAsString();
+      return new PubDartdocData.fromJson(
+          convert.json.decode(content) as Map<String, dynamic>);
+    } catch (e, st) {
+      _logger.warning('Unable to parse $_pubDataFileName.', e, st);
+      return null;
+    }
+  }
 }
diff --git a/app/lib/scorecard/models.dart b/app/lib/scorecard/models.dart
index bddbade7ad..ef9ac10d5e 100644
--- a/app/lib/scorecard/models.dart
+++ b/app/lib/scorecard/models.dart
@@ -4,6 +4,7 @@
 
 import 'dart:convert';
 import 'dart:io';
+import 'dart:math' as math;
 
 import 'package:gcloud/db.dart' as db;
 import 'package:json_annotation/json_annotation.dart';
@@ -150,9 +151,14 @@ class ScoreCard extends db.ExpandoModel {
     PanaReport panaReport,
     DartdocReport dartdocReport,
   }) {
-    healthScore = (panaReport?.healthScore ?? 0.0) *
-        (0.9 + ((dartdocReport?.coverageScore ?? 1.0) * 0.1));
-    maintenanceScore = panaReport?.maintenanceScore ?? 0.0;
+    healthScore = _applySuggestions(
+      panaReport?.healthScore ?? 0.0,
+      dartdocReport?.healthSuggestions,
+    );
+    maintenanceScore = _applySuggestions(
+      panaReport?.maintenanceScore ?? 0.0,
+      dartdocReport?.maintenanceSuggestions,
+    );
     platformTags = panaReport?.platformTags ?? <String>[];
     reportTypes = [
       panaReport == null ? null : ReportType.pana,
@@ -162,6 +168,15 @@ class ScoreCard extends db.ExpandoModel {
       ..sort();
     panaReport?.flags?.forEach(addFlag);
   }
+
+  double _applySuggestions(double score, List<Suggestion> suggestions) {
+    suggestions?.forEach((s) {
+      if (s.score != null) {
+        score -= s.score / 100.0;
+      }
+    });
+    return math.max(score, 0.0);
+  }
 }
 
 /// Detail of a specific report for a given PackageVersion.
@@ -381,12 +396,19 @@ class DartdocReport implements ReportData {
 
   final double coverageScore;
 
-  final List<Suggestion> suggestions;
+  /// Suggestions related to the package health score.
+  @JsonKey(includeIfNull: false)
+  final List<Suggestion> healthSuggestions;
+
+  /// Suggestions related to the package maintenance score.
+  @JsonKey(includeIfNull: false)
+  final List<Suggestion> maintenanceSuggestions;
 
   DartdocReport({
     @required this.reportStatus,
     @required this.coverageScore,
-    @required this.suggestions,
+    @required this.healthSuggestions,
+    @required this.maintenanceSuggestions,
   });
 
   factory DartdocReport.fromJson(Map<String, dynamic> json) =>
diff --git a/app/lib/scorecard/models.g.dart b/app/lib/scorecard/models.g.dart
index 46453bf708..8f9388b6ec 100644
--- a/app/lib/scorecard/models.g.dart
+++ b/app/lib/scorecard/models.g.dart
@@ -117,15 +117,29 @@ DartdocReport _$DartdocReportFromJson(Map<String, dynamic> json) {
   return DartdocReport(
       reportStatus: json['reportStatus'] as String,
       coverageScore: (json['coverageScore'] as num)?.toDouble(),
-      suggestions: (json['suggestions'] as List)
+      healthSuggestions: (json['healthSuggestions'] as List)
+          ?.map((e) =>
+              e == null ? null : Suggestion.fromJson(e as Map<String, dynamic>))
+          ?.toList(),
+      maintenanceSuggestions: (json['maintenanceSuggestions'] as List)
           ?.map((e) =>
               e == null ? null : Suggestion.fromJson(e as Map<String, dynamic>))
           ?.toList());
 }
 
-Map<String, dynamic> _$DartdocReportToJson(DartdocReport instance) =>
-    <String, dynamic>{
-      'reportStatus': instance.reportStatus,
-      'coverageScore': instance.coverageScore,
-      'suggestions': instance.suggestions
-    };
+Map<String, dynamic> _$DartdocReportToJson(DartdocReport instance) {
+  var val = <String, dynamic>{
+    'reportStatus': instance.reportStatus,
+    'coverageScore': instance.coverageScore,
+  };
+
+  void writeNotNull(String key, dynamic value) {
+    if (value != null) {
+      val[key] = value;
+    }
+  }
+
+  writeNotNull('healthSuggestions', instance.healthSuggestions);
+  writeNotNull('maintenanceSuggestions', instance.maintenanceSuggestions);
+  return val;
+}