xAPI（ADL）的出现并非意外事件。 TinCan的讨论进行了很长时间，在讨论新规范时，大量开放论坛如火如荼。只有经过充分讨论，ADL才会发布该规范。然后，在许多使用xApi的公司进行实际工作之后，出现了CMI5。
然后出现了来自IMS全球学习协会的一个类似规范Caliper。
xAPI和Caliper之间的明显相似之处促使开发人员和内容提供者澄清了一个或两个规范（当前都针对标准化）的实现方面的差异。
xAPI和Caliper社区都表达了对对这两个规范的成本有效支持的担忧，这导致ADL和IMS都要求查看它们是否可以协调。
这是一个简短的答案“ IMS”（链接）
a）Caliper和xAPI的起源非常不同。xAPI的核心是实现电子和物理性能的任何类型的经验和证据跟踪，而不仅限于基于Web的课程（SCORM就是这种情况）。Caliper是IMS Learning Analytics框架的体现，Sensor API和Metric Profile是该框架的前两个组件。xAPI和Caliper不等效。收养不应是“一个或另一个”，而是一个“一马当先”的决定。
b）虽然xAPI（演员/动词/对象）和卡尺（演员/动作/活动）都使用基于三重语句结构的数据模型，但对象和活动定义的详细结构和用法却存在很大差异。但是，每个规范都应该可以使用对方的动词/动作；
这是简短的答案“ ADL”（链接）。
As xAPI has matured, so too has a similar specification from the IMS Global Learning Consortium called Caliper. There are notable similarities between xAPI and Caliper, which has caused adopters and vendors to clarify implementation differences of one or both specifications (both of which are now targeting standardization). Both communities supporting xAPI and Caliper have expressed concerns about being able to cost-effectively support both specs, which led to inquiries to both ADL Initiative and IMS about whether alignment of the two would be possible.
xAPI（演员/动词/对象）和游标卡尺（演员/动作/活动）使用基于三元运算符结构的数据模型，在对象和活动定义的详细结构和用法上存在很大差异。显然演员和动词/动作是相同的，只是对象/活动是不同的？
我使用xAPI已有很长时间了，但是Caliper对我并不熟悉。我不得不稍微研究一下文档（链接和其他内容）。
我将立即说，我个人没有发现任何重大差异。 xAPI语句（Activites）中所谓的事件在Caliper中称为事件。
我提请注意Caliper中所谓的“度量”的存在，但是描述非常抽象，我找不到实际的例子。
The Caliper information model defines a number of metric profiles, each of which models a learning activity or a supporting activity that helps facilitate learning. A metric profile’s raison d’etre is to encourage vocabulary standardization and re-use among application providers delivering complementary, albeit competing capabilities that collect learning activity data. Each profile provides a domain-specific set of terms and concepts that application designers and developers can draw upon to describe common user interactions in a consistent manner using a shared vocabulary. Annotating a reading, playing a video, taking a test, or grading an assignment submission represent a few examples of the many activities or events that Caliper’s metric profiles attempt to describe.
将每个度量标准配置文件视为一个独立的逻辑容器，或者一个或多个Caliper事件的集合，这些事件一起有助于描述一组相互关联的活动。度量标准配置文件中包括的每种事件类型都对可用于描述学习活动的各种实体和动作施加了约束。在以下标题下的每个个人资料描述中概述了词汇限制
IMS网站上有很多“漂亮的图片”，但是它们进一步增强了这种差别很小的感觉。
从授权和存储机制（LRS）的角度来看，实际上没有区别，xApi中的JSON和Caliper中的JSON-LD之间的区别对我而言并不重要。那些。在这些问题上没有区别。
让我们看一下JSON xApi和Caliper
xApi的示例
{
"actor": {
"name": "Sally Glider",
"mbox": "mailto:sally@example.com"
},
"verb": {
"id": "http://adlnet.gov/expapi/verbs/completed",
"display": { "en-US": "completed" }
},
"object": {
"id": "http://example.com/activities/hang-gliding-test",
"definition": {
"type": "http://adlnet.gov/expapi/activities/assessment",
"name": { "en-US": "Hang Gliding Test" },
"description": {
"en-US": "The Solo Hang Gliding test, consisting of a timed flight from the peak of Mount Magazine"
},
"extensions": {
"http://example.com/gliderClubId": "test-435"
}
}
},
"result": {
"completion": true,
"success": true,
"score": {
"scaled": 0.95
},
"extensions": {
"http://example.com/flight/averagePitch": 0.05
}
},
"context": {
"instructor": {
"name": "Irene Instructor",
"mbox": "mailto:irene@example.com"
},
"contextActivities":{
"parent": { "id": "http://example.com/activities/hang-gliding-class-a" }
"grouping": { "id": "http://example.com/activities/hang-gliding-school" }
},
"extensions": {
"http://example.com/weatherConditions": "rainy"
}
},
"timestamp": "2012-07-05T18:30:32.360Z",
"stored": "2012-07-05T18:30:33.540Z",
"authority": {
"name": "Irene Instructor",
"mbox": "mailto:irene@example.com"
}
}卡尺
{
"sensor": "https://example.edu/sensors/1",
"sendTime": "2018-11-15T11:05:01.000Z",
"dataVersion": "http://purl.imsglobal.org/ctx/caliper/v1p1",
"data": [
{
"@context": "http://purl.imsglobal.org/ctx/caliper/v1p1",
"id": "https://example.edu/users/554433",
"type": "Person",
"dateCreated": "2018-08-01T06:00:00.000Z",
"dateModified": "2018-09-02T11:30:00.000Z"
},
{
"@context": "http://purl.imsglobal.org/ctx/caliper/v1p1",
"id": "https://example.edu/terms/201801/courses/7/sections/1/assess/1?ver=v1p0",
"type": "Assessment",
"name": "Quiz One",
"items": [
{
"id": "https://example.edu/terms/201801/courses/7/sections/1/assess/1/items/1",
"type": "AssessmentItem"
},
{
"id": "https://example.edu/terms/201801/courses/7/sections/1/assess/1/items/2",
"type": "AssessmentItem"
},
{
"id": "https://example.edu/terms/201801/courses/7/sections/1/assess/1/items/3",
"type": "AssessmentItem"
}
],
"dateCreated": "2018-08-01T06:00:00.000Z",
"dateModified": "2018-09-02T11:30:00.000Z",
"datePublished": "2018-08-15T09:30:00.000Z",
"dateToActivate": "2018-08-16T05:00:00.000Z",
"dateToShow": "2018-08-16T05:00:00.000Z",
"dateToStartOn": "2018-08-16T05:00:00.000Z",
"dateToSubmit": "2018-09-28T11:59:59.000Z",
"maxAttempts": 2,
"maxScore": 15.0,
"maxSubmits": 2,
"version": "1.0"
},
{
"@context": "http://purl.imsglobal.org/ctx/caliper/v1p1",
"id": "https://example.edu",
"type": "SoftwareApplication",
"version": "v2"
},
{
"@context": "http://purl.imsglobal.org/ctx/caliper/v1p1",
"id": "https://example.edu/terms/201801/courses/7/sections/1",
"type": "CourseSection",
"academicSession": "Fall 2018",
"courseNumber": "CPS 435-01",
"name": "CPS 435 Learning Analytics, Section 01",
"category": "seminar",
"subOrganizationOf": {
"id": "https://example.edu/terms/201801/courses/7",
"type": "CourseOffering",
"courseNumber": "CPS 435"
},
"dateCreated": "2018-08-01T06:00:00.000Z"
},
{
"@context": "http://purl.imsglobal.org/ctx/caliper/v1p1",
"id": "urn:uuid:c51570e4-f8ed-4c18-bb3a-dfe51b2cc594",
"type": "AssessmentEvent",
"actor": "https://example.edu/users/554433",
"action": "Started",
"object": "https://example.edu/terms/201801/courses/7/sections/1/assess/1?ver=v1p0",
"generated": {
"id": "https://example.edu/terms/201801/courses/7/sections/1/assess/1/users/554433/attempts/1",
"type": "Attempt",
"assignee": "https://example.edu/users/554433",
"assignable": "https://example.edu/terms/201801/courses/7/sections/1/assess/1?ver=v1p0",
"count": 1,
"dateCreated": "2018-11-15T10:15:00.000Z",
"startedAtTime": "2018-11-15T10:15:00.000Z"
},
"eventTime": "2018-11-15T10:15:00.000Z",
"edApp": "https://example.edu",
"group": "https://example.edu/terms/201801/courses/7/sections/1",
"membership": {
"id": "https://example.edu/terms/201801/courses/7/sections/1/rosters/1",
"type": "Membership",
"member": "https://example.edu/users/554433",
"organization": "https://example.edu/terms/201801/courses/7/sections/1",
"roles": [ "Learner" ],
"status": "Active",
"dateCreated": "2018-08-01T06:00:00.000Z"
},
"session": {
"id": "https://example.edu/sessions/1f6442a482de72ea6ad134943812bff564a76259",
"type": "Session",
"startedAtTime": "2018-11-15T10:00:00.000Z"
}
},
{
"@context": "http://purl.imsglobal.org/ctx/caliper/v1p1",
"id": "urn:uuid:dad88464-0c20-4a19-a1ba-ddf2f9c3ff33",
"type": "AssessmentEvent",
"actor": "https://example.edu/users/554433",
"action": "Submitted",
"object": "https://example.edu/terms/201801/courses/7/sections/1/assess/1?ver=v1p0",
"generated": {
"id": "https://example.edu/terms/201801/courses/7/sections/1/assess/1/users/554433/attempts/1",
"type": "Attempt",
"assignee": "https://example.edu/users/554433",
"assignable": "https://example.edu/terms/201801/courses/7/sections/1/assess/1?ver=v1p0",
"count": 1,
"dateCreated": "2018-11-15T10:15:00.000Z",
"startedAtTime": "2018-11-15T10:15:00.000Z",
"endedAtTime": "2018-11-15T10:55:12.000Z",
"duration": "PT40M12S"
},
"eventTime": "2018-11-15T10:25:30.000Z",
"edApp": "https://example.edu",
"group": "https://example.edu/terms/201801/courses/7/sections/1",
"membership": {
"id": "https://example.edu/terms/201801/courses/7/sections/1/rosters/1",
"type": "Membership",
"member": "https://example.edu/users/554433",
"organization": "https://example.edu/terms/201801/courses/7/sections/1",
"roles": ["Learner"],
"status": "Active",
"dateCreated": "2018-08-01T06:00:00.000Z"
},
"session": {
"id": "https://example.edu/sessions/1f6442a482de72ea6ad134943812bff564a76259",
"type": "Session",
"startedAtTime": "2018-11-15T10:00:00.000Z"
}
},
{
"@context": "http://purl.imsglobal.org/ctx/caliper/v1p1",
"id": "urn:uuid:a50ca17f-5971-47bb-8fca-4e6e6879001d",
"type": "GradeEvent",
"actor": {
"id": "https://example.edu/autograder",
"type": "SoftwareApplication",
"version": "v2"
},
"action": "Graded",
"object": {
"id": "https://example.edu/terms/201801/courses/7/sections/1/assess/1/users/554433/attempts/1",
"type": "Attempt",
"assignee": "https://example.edu/users/554433",
"assignable": "https://example.edu/terms/201801/courses/7/sections/1/assess/1?ver=v1p0",
"count": 1,
"dateCreated": "2018-11-15T10:15:00.000Z",
"startedAtTime": "2018-11-15T10:15:00.000Z",
"endedAtTime": "2018-11-15T10:55:12.000Z",
"duration": "PT40M12S"
},
"eventTime": "2018-11-15T10:57:06.000Z",
"edApp": "https://example.edu",
"generated": {
"id": "https://example.edu/terms/201801/courses/7/sections/1/assess/1/users/554433/attempts/1/scores/1",
"type": "Score",
"attempt": "https://example.edu/terms/201801/courses/7/sections/1/assess/1/users/554433/attempts/1",
"maxScore": 15.0,
"scoreGiven": 10.0,
"scoredBy": "https://example.edu/autograder",
"comment": "auto-graded exam",
"dateCreated": "2018-11-15T10:56:00.000Z"
},
"group": "https://example.edu/terms/201801/courses/7/sections/1"
}
]
}我必须承认，我无法自己确定这些规格之间的重大差异。
短语
IMS学习分析框架以及Sensor API和度量标准配置文件是该框架的前两个组件表示显然我们应该期待框架的出现。但是我找不到关于它的信息。
我不知道为什么两个著名的组织提交了我个人认为相似的规范。例如，SCORM（ADL）和IMS CP的“共存”历史表明，标准可以相互补充。这次我没有看到这样的增加。