xAPI Specification Knowledge Base

Provide comprehensive guidance on xAPI (Experience API) specification for educational assessment and learning analytics.

Core Concepts

Statement Structure

An xAPI Statement follows the "Actor-Verb-Object" pattern with optional Result and Context:

{ "actor": { }, // Who performed the action "verb": { }, // What action was performed "object": { }, // What was acted upon "result": { }, // Outcome of the action (optional) "context": { }, // Additional context (optional) "timestamp": "", // When the action occurred "id": "" // Unique statement identifier (UUID) }

Required Fields

• Actor - Agent or Group performing the action

• Verb - Action taken (URI + display name)

• Object - Activity, Agent, or Statement Reference

Actor Types

Agent (single learner):

{ "objectType": "Agent", "name": "Learner Name", "mbox": "mailto:learner@example.com" }

Account-based identification (recommended for LMS):

{ "objectType": "Agent", "account": { "homePage": "https://lms.example.com", "name": "user123" } }

Verb Structure

Define verbs with URI identifier and display text:

{ "id": "http://adlnet.gov/expapi/verbs/answered", "display": { "en-US": "answered" } }

Consult references/verbs.md for the complete ADL and cmi5 verb registry.

Object (Activity) Structure

{ "objectType": "Activity", "id": "https://example.com/activities/quiz-123", "definition": { "name": { "en-US": "Quiz on xAPI Basics" }, "description": { "en-US": "A quiz testing knowledge of xAPI" }, "type": "http://adlnet.gov/expapi/activities/assessment" } }

Result Structure

Capture assessment outcomes:

{ "score": { "scaled": 0.85, "raw": 85, "min": 0, "max": 100 }, "success": true, "completion": true, "response": "choice-a", "duration": "PT30S" }

Duration format: ISO 8601 duration (PT = Period Time, e.g., PT1H30M = 1 hour 30 minutes)

Context Structure

Provide additional information about the learning experience:

{ "registration": "uuid-for-attempt", "contextActivities": { "parent": [{ "id": "https://example.com/course-123" }], "grouping": [{ "id": "https://example.com/program-abc" }], "category": [{ "id": "https://w3id.org/xapi/cmi5/context/categories/cmi5" }] }, "platform": "Example LMS", "language": "en-US" }

Interaction Types for Assessments

xAPI supports these interaction types for quiz questions:

Type Description Use Case

true-false

Binary choice Yes/No, True/False questions

choice

Multiple choice Single or multiple selection

fill-in

Text input Short answer questions

long-fill-in

Long text Essay questions

matching

Pair matching Match items from two lists

performance

Task steps Procedural tasks

sequencing

Order items Arrange in correct sequence

likert

Scale rating Survey/opinion questions

numeric

Number input Mathematical answers

Consult references/interaction-types.md for detailed examples of each type.

Activity Types

Common activity types for educational contexts:

Category Type URI Use Case

Assessment http://adlnet.gov/expapi/activities/assessment

Quizzes, exams

Question http://adlnet.gov/expapi/activities/cmi.interaction

Individual questions

Course http://adlnet.gov/expapi/activities/course

Course container

Module http://adlnet.gov/expapi/activities/module

Course sections

Lesson http://adlnet.gov/expapi/activities/lesson

Individual lessons

Consult references/activity-types.md for the complete registry.

cmi5 Profile

cmi5 is a standardized xAPI profile for e-learning. Key requirements:

• Defined verbs: launched, initialized, completed, passed, failed, abandoned, waived, terminated

• Mandatory context: registration, sessionId, masteryScore

• Required extensions: sessionId, launchMode, launchURL

For cmi5-compliant statements, consult references/cmi5-profile.md .

Statement Generation Workflow

To generate a valid xAPI statement:

• Identify the Actor (learner/user information)

• Select appropriate Verb from ADL registry

• Define the Object (activity being tracked)

• Include Result for assessment outcomes

• Add Context for hierarchical relationships

• Generate UUID for statement ID

• Add timestamp in ISO 8601 format

Validation Checklist

Validate statements against these criteria:

Structural validation:

• Actor has valid identifier (mbox, account, or openid)

• Verb has id (URI) and display (language map)

• Object has id and objectType

Vocabulary validation:

• Verb URI matches ADL/cmi5 registry

• Activity type URI is valid

cmi5 validation:

• Context includes registration UUID

• Context includes sessionId extension

• Correct verb sequence (launched → initialized → ... → terminated)

Interaction validation:

• interactionType matches response format

• correctResponsesPattern format matches interactionType

• choices/scale/source/target arrays are valid for type

Additional Resources

Reference Files

Detailed specifications and registries:

• references/verbs.md

• Complete ADL and cmi5 verb registry

• references/activity-types.md

• Activity type URIs and usage

• references/interaction-types.md

• Detailed interaction type examples

• references/cmi5-profile.md

• cmi5 requirements and extensions

External Resources

• xAPI Specification

• ADL Vocabulary

• cmi5 Specification