This document is written to help professors understand how a final grade for a
course is computed.
Course grading is the process of taking all of the problems scores for a student
in a course and generating a final score (and corresponding letter grade). This
grading process can be split into two phases - totaling sections and section
weighting.
## Totaling sections
The process of totaling sections is to get a percentage score (between 0.0 and
1.0) for every section in the course. A section is any module that is a direct
child of a chapter. For example, psets, labs, and sequences are all common
sections. Only the *percentage* on the section will be available to compute the
final grade, *not* the final number of points earned / possible.
**For a section to be included in the final grade, the policies file must set
graded = True for the section.**
For each section, the grading function retrieves all problems within the
section. The section percentage is computed as (total points earned) / (total
points possible).
### Weighting Problems
In some cases, one might want to give weights to problems within a section. For
example, a final exam might contain 4 questions each worth 1 point by default.
This means each question would by default have the same weight. If one wanted
the first problem to be worth 50% of the final exam, the policy file could specify
weights of 30, 10, 10, and 10 to the 4 problems, respectively.
Note that the default weight of a problem **is not 1.** The default weight of a
problem is the module's max_grade.
If weighting is set, each problem is worth the number of points assigned, regardless of the number of responses it contains.
Consider a Homework section that contains two problems.
<problem display_name=”Problem 1”>
<numericalresponse> ... </numericalreponse>
</problem>
and
<problem display_name=”Problem 2”>
<numericalresponse> ... </numericalreponse>
<numericalresponse> ... </numericalreponse>
<numericalresponse> ... </numericalreponse>
</problem>
Without weighting, Problem 1 is worth 25% of the assignment, and Problem 2 is worth 75% of the assignment.
Weighting for the problems can be set in the policy.json file.
"problem/problem1": {
"weight": 2
},
"problem/problem2": {
"weight": 2
},
With the above weighting, Problems 1 and 2 are each worth 50% of the assignment.
Please note: When problems have weight, the point value is automatically included in the display name *except* when “weight”: 1.When “weight”: 1, no visual change occurs in the display name, leaving the point value open to interpretation to the student.
## Section Weighting
Once each section has a percentage score, we must total those sections into a
final grade. Of course, not every section has equal weight in the final grade.
The policies for weighting sections into a final grade are specified in the
grading_policy.json file.
The grading_policy.json file specifies several sub-graders that are each given
a weight and factored into the final grade. There are currently two types of
sub-graders, section format graders and single section graders.
We will use this simple example of a grader with one section format grader and
one single section grader.
"GRADER" : [
{
"type" : "Homework",
"min_count" : 12,
"drop_count" : 2,
"short_label" : "HW",
"weight" : 0.4
},
{
"type" : "Final",
"name" : "Final Exam",
"short_label" : "Final",
"weight" : 0.6
}
]
### Section Format Graders
A section format grader grades a set of sections with the same format, as
defined in the course policy file. To make a vertical named Homework1 be graded
by the Homework section format grader, the following definition would be in the
course policy file.
"vertical/Homework1": {
"display_name": "Homework 1",
"graded": true,
"format": "Homework"
},
In the example above, the section format grader declares that it will expect to
find at least 12 sections with the format "Homework". It will drop the lowest 2.
All of the homework assignments will have equal weight, relative to each other
(except, of course, for the assignments that are dropped).
This format supports forecasting the number of homework assignments. For
example, if the course only has 3 homeworks written, but the section format
grader has been told to expect 12, the missing 9 will have an assumed 0% and
will still show up in the grade breakdown.
A section format grader will also show the average of that section in the grade
breakdown (shown on the Progress page, gradebook, etc.).
### Single Section Graders
A single section grader grades exactly that - a single section. If a section
is found with a matching format and display name then the score of that section
is used. If not, a score of 0% is assumed.
### Combining sub-graders
The final grade is computed by taking the score and weight of each sub grader.
In the above example, homework will be 40% of the final grade. The final exam
will be 60% of the final grade.
## Displaying the final grade
The final grade is then rounded up to the nearest percentage point. This is so
the system can consistently display a percentage without worrying whether the
displayed percentage has been rounded up or down (potentially misleading the
* This was written assuming the reader has no prior programming/CS knowledge and has jumped cold turkey into the edX platform.
* To educate the reader on how to build and maintain the back end structure of the course content. This is important for debugging and standardization.
* After reading this, you should be able to add content to a course and make sure it shows up in the courseware and does not break the code.
* __Prerequisites:__ it would be helpful to know a little bit about xml. Here is a [simple example](http://www.ultraslavonic.info/intro-to-xml/) if you've never seen it before.
## Outline
* First, we will show a sample course structure as a case study/model of how xml and files in a course are organized to introductory understanding.
* More technical details are below, including discussion of some special cases.
## Introduction
* The course is organized hierarchically. We start by describing course-wide parameters, then break the course into chapters, and then go deeper and deeper until we reach a specific pset, video, etc.
* You could make an analogy to finding a green shirt in your house - front door -> bedroom -> closet -> drawer -> shirts -> green shirt
## Case Study
Let's jump right in by looking at the directory structure of a very simple toy course:
toy/
course
course.xml
problem
policies
roots
The only top level file is `course.xml`, which should contain one line, looking something like this:
This gives all the information to uniquely identify a particular run of any course--which organization is producing the course, what the course name is, and what "run" this is, specified via the `url_name` attribute.
Obviously, this doesn't actually specify any of the course content, so we need to find that next. To know where to look, you need to know the standard organizational structure of our system: _course elements are uniquely identified by the combination `(category, url_name)`_. In this case, we are looking for a `course` element with the `url_name` "2012_Fall". The definition of this element will be in `course/2012_Fall.xml`. Let's look there next:
Aha. Now we found some content. We can see that the course is organized hierarchically, in this case with only one chapter, with `url_name` "Overview". The chapter contains a `videosequence` and a `video`, with the sequence containing a problem and another video. When viewed in the courseware, chapters are shown at the top level of the navigation accordion on the left, with any elements directly included in the chapter below.
Looking at this file, we can see the course structure, and the youtube urls for the videos, but what about the "warmup" problem? There is no problem content here! Where should we look? This is a good time to pause and try to answer that question based on our organizational structure above.
As you hopefully guessed, the problem would be in `problem/warmup.xml`. (Note: This tutorial doesn't discuss the xml format for problems--there are chapters of edx4edx that describe it.) This is an instance of a _pointer tag:_ any xml tag with only the category and a url_name attribute will point to the file `{category}/{url_name}.xml`. For example, this means that our toy `course.xml` could have also been written as
In fact, this is the recommended structure for real courses--putting each chapter into its own file makes it easy to have different people work on each without conflicting or having to merge. Similarly, as sequences get large, it can be handy to split them out as well (in `sequence/{url_name}.xml`, of course).
Note that the `url_name` is only specified once per element--either the inline definition, or in the pointer tag.
## Policy files
We still haven't looked at two of the directoies in the top-level listing above: `policies` and `roots`. Let's look at policies next. The policy directory contains one file:
policies:
2012_Fall.json
and that file is named {course-url_name}.json. As you might expect, this file contains a policy for the course. In our example, it looks like this:
2012_Fall.json:
{
"course/2012_Fall": {
"graceperiod": "2 days 5 hours 59 minutes 59 seconds",
"start": "2015-07-17T12:00",
"display_name": "Toy Course"
},
"chapter/Overview": {
"display_name": "Overview"
},
"videosequence/Toy_Videos": {
"display_name": "Toy Videos",
"format": "Lecture Sequence"
},
"problem/warmup": {
"display_name": "Getting ready for the semester"
},
"video/Video_Resources": {
"display_name": "Video Resources"
},
"video/Welcome": {
"display_name": "Welcome"
}
}
The policy specifies metadata about the content elements--things which are not inherent to the definition of the content, but which describe how the content is presented to the user and used in the course. See below for a full list of metadata attributes; as the example shows, they include `display_name`, which is what is shown when this piece of content is referenced or shown in the courseware, and various dates and times, like `start`, which specifies when the content becomes visible to students, and various problem-specific parameters like the allowed number of attempts. One important point is that some metadata is inherited: for example, specifying the start date on the course makes it the default for every element in the course. See below for more details.
It is possible to put metadata directly in the xml, as attributes of the appropriate tag, but using a policy file has two benefits: it puts all the policy in one place, making it easier to check that things like due dates are set properly, and it allows the content definitions to be easily used in another run of the same course, with the same or similar content, but different policy.
## Roots
The last directory in the top level listing is `roots`. In our toy course, it contains a single file:
roots/
2012_Fall.xml
This file is identical to the top-level `course.xml`, containing
In fact, the top level `course.xml` is a symbolic link to this file. When there is only one run of a course, the roots directory is not really necessary, and the top-level course.xml file can just specify the `url_name` of the course. However, if we wanted to make a second run of our toy course, we could add another file called, e.g., `roots/2013_Spring.xml`, containing
After creating `course/2013_Spring.xml` with the course structure (possibly as a symbolic link or copy of `course/2012_Fall.xml` if no content was changing), and `policies/2013_Spring.json`, we would have two different runs of the toy course in the course repository. Our build system understands this roots structure, and will build a course package for each root. (Dev note: if you're using a local development environment, make the top level `course.xml` point to the desired root, and check out the repo multiple times if you need multiple runs simultaneously).
That's basically all there is to the organizational structure. Read the next section for details on the tags we support, including some special case tags like `customtag` and `html` invariants, and look at the end for some tips that will make the editing process easier.
----------
# Tag types
* `abtest` -- Support for A/B testing. TODO: add details..
* `chapter` -- top level organization unit of a course. The courseware display code currently expects the top level `course` element to contain only chapters, though there is no philosophical reason why this is required, so we may change it to properly display non-chapters at the top level.
* `conditional` -- conditional element, which shows one or more modules only if certain conditions are satisfied.
* `course` -- top level tag. Contains everything else.
* `customtag` -- render an html template, filling in some parameters, and return the resulting html. See below for details.
* `discussion` -- Inline discussion forum
* `html` -- a reference to an html file.
* `error` -- don't put these in by hand :) The internal representation of content that has an error, such as malformed xml or some broken invariant. You may see this in the xml once the CMS is in use...
* `problem` -- a problem. See elsewhere in edx4edx for documentation on the format.
* `problemset` -- logically, a series of related problems. Currently displayed vertically. May contain explanatory html, videos, etc.
* `sequential` -- a sequence of content, currently displayed with a horizontal list of tabs. If possible, use a more semantically meaningful tag (currently, we only have `videosequence`).
* `vertical` -- a sequence of content, displayed vertically. Content will be accessed all at once, on the right part of the page. No navigational bar. May have to use browser scroll bars. Content split with separators. If possible, use a more semantically meaningful tag (currently, we only have `problemset`).
* `video` -- a link to a video, currently expected to be hosted on youtube.
* `videosequence` -- a sequence of videos. This can contain various non-video content; it just signals to the system that this is logically part of an explanatory sequence of content, as opposed to say an exam sequence.
## Tag details
### Container tags
Container tags include `chapter`, `sequential`, `videosequence`, `vertical`, and `problemset`. They are all specified in the same way in the xml, as shown in the tutorial above.
### `course`
`course` is also a container, and is similar, with one extra wrinkle: the top level pointer tag _must_ have `org` and `course` attributes specified--the organization name, and course name. Note that `course` is referring to the platonic ideal of this course (e.g. "6.002x"), not to any particular run of this course. The `url_name` should be the particular run of this course.
### `conditional`
`conditional` is as special kind of container tag as well. Here are two examples:
The condition can be either `require_completed`, in which case the required modules must be completed, or `require_attempted`, in which case the required modules must have been attempted.
The required modules are specified as a set of `tag`/`url_name`, joined by an ampersand.
### `customtag`
When we see `<customtagimpl="special"animal="unicorn"hat="blue"/>`, we will:
* look for a file called `custom_tags/special` in your course dir.
* render it as a mako template, passing parameters {'animal':'unicorn', 'hat':'blue'}, generating html. (Google `mako` for template syntax, or look at existing examples).
Since `customtag` is already a pointer, there is generally no need to put it into a separate file--just use it in place: <customtag url_name="my_custom_tag" impl="blah" attr1="..."/>
### `discussion`
The discussion tag embeds an inline discussion module. The XML format is:
* `for`: A string that describes the discussion. Purely for descriptive purposes (to the student).
* `id`: The identifier that the discussion forum service uses to refer to this inline discussion module. Since the `id` must be unique and lives in a common namespace with all other courses, the preferred convention is to use `<course_name>_<course_run>_<descriptor>` as in the above example. The `id` should be "machine-friendly", e.g. use alphanumeric characters, underscores. Do **not** use a period (e.g. `6.002x_Fall_2012_Overview`).
* `discussion_category`: The inline module will be indexed in the main "Discussion" tab of the course. The inline discussions are organized into a directory-like hierarchy. Note that the forward slash indicates depth, as in conventional filesytems. In the above example, this discussion module will show up in the following "directory":
```
Week 1 / Overview / Course overview
```
Further discussion on `discussion_category`:
Note that the `for` tag has been appended to the end of the `discussion_category`. This can often lead into deeply nested subforums, which may not be intended. In the above example, if we were to use instead:
this discussion module would show up in the main forums as:
```
Week 1 / Course overview
```
which is more succinct.
### `html`
Most of our content is in xml, but some html content may not be proper xml (all tags matched, single top-level tag, etc), since browsers are fairly lenient in what they'll display. So, there are two ways to include html content:
* If your html content is in a proper xml format, just put it in `html/{url_name}.xml`.
* If your html content is not in proper xml format, you can put it in `html/{filename}.html`, and put `<htmlfilename={filename}/>` in `html/{filename}.xml`. This allows another level of indirection, and makes sure that we can read the xml file and then just return the actual html content without trying to parse it.
### `video`
Videos have an attribute youtube, which specifies a series of speeds + youtube videos id:
This video has been encoded at 4 different speeds: 0.75x, 1x, 1.25x, and 1.5x.
## More on `url_name`s
Every content element (within a course) should have a unique id. This id is formed as `{category}/{url_name}`, or automatically generated from the content if `url_name` is not specified. Categories are the different tag types ('chapter', 'problem', 'html', 'sequential', etc). Url_name is a string containing a-z, A-Z, dot (.), underscore (_), and ':'. This is what appears in urls that point to this object.
Colon (':') is special--when looking for the content definition in an xml, ':' will be replaced with '/'. This allows organizing content into folders. For example, given the pointer tag
we would look for the problem definition in `problem/conceptual/add_apples_and_oranges.xml`. (There is a technical reason why we can't just allow '/' in the url_name directly.)
__IMPORTANT__: A student's state for a particular content element is tied to the element id, so the automatic id generation if only ok for elements that do not need to store any student state (e.g. verticals or customtags). For problems, sequentials, and videos, and any other element where we keep track of what the student has done and where they are at, you should specify a unique `url_name`. Of course, any content element that is split out into a file will need a `url_name` to specify where to find the definition. When the CMS comes online, it will use these ids to enable content reuse, so if there is a logical name for something, please do specify it.
-----
## Policy files
* A policy file is useful when running different versions of a course e.g. internal, external, fall, spring, etc. as you can change due dates, etc, by creating multiple policy files.
* A policy file provides information on the metadata of the course--things that are not inherent to the definitions of the contents, but that may vary from run to run.
* Note: We will be expanding our understanding and format for metadata in the not-too-distant future, but for now it is simply a set of key-value pairs.
### Policy file location
* The policy for a course run `some_url_name` should live in `policies/some_url_name/policy.json` (NOTE: the old format of putting it in `policies/some_url_name.json` will also work, but we suggest using the subdirectory to have all the per-course policy files in one place)
* Grading policy files go in `policies/some_url_name/grading_policy.json` (if there's only one course run, can also put it directly in the course root: `/grading_policy.json`)
### Policy file contents
* The file format is "json", and is best shown by example, as in the tutorial above (though also feel free to google :)
* The expected contents are a dictionary mapping from keys to values (syntax "{ key : value, key2 : value2, etc}")
* Keys are in the form "{category}/{url_name}", which should uniquely identify a content element.
Values are dictionaries of the form {"metadata-key" : "metadata-value"}.
* The order in which things appear does not matter, though it may be helpful to organize the file in the same order as things appear in the content.
* NOTE: json is picky about commas. If you have trailing commas before closing braces, it will complain and refuse to parse the file. This can be irritating at first.
Supported fields at the course level:
* "start" -- specify the start date for the course. Format-by-example: "2012-09-05T12:00".
* "advertised_start" -- specify what you want displayed as the start date of the course in the course listing and course about pages. This can be useful if you want to let people in early before the formal start. Format-by-example: "2012-09-05T12:00".
* "disable_policy_graph" -- set to true (or "Yes"), if the policy graph should be disabled (ie not shown).
* "enrollment_start", "enrollment_end" -- when can students enroll? (if not specified, can enroll anytime). Same format as "start".
* "end" -- specify the end date for the course. Format-by-example: "2012-11-05T12:00".
* "end_of_course_survey_url" -- a url for an end of course survey -- shown after course is over, next to certificate download links.
* "tabs" -- have custom tabs in the courseware. See below for details on config.
* "discussion_blackouts" -- An array of time intervals during which you want to disable a student's ability to create or edit posts in the forum. Moderators, Community TAs, and Admins are unaffected. You might use this during exam periods, but please be aware that the forum is often a very good place to catch mistakes and clarify points to students. The better long term solution would be to have better flagging/moderation mechanisms, but this is the hammer we have today. Format by example: [["2012-10-29T04:00", "2012-11-03T04:00"], ["2012-12-30T04:00", "2013-01-02T04:00"]]
* "show_calculator" (value "Yes" if desired)
* "days_early_for_beta" -- number of days (floating point ok) early that students in the beta-testers group get to see course content. Can also be specified for any other course element, and overrides values set at higher levels.
* "cohort_config" : dictionary with keys
- "cohorted" : boolean. Set to true if this course uses student cohorts. If so, all inline discussions are automatically cohorted, and top-level discussion topics are configurable via the cohorted_discussions list. Default is not cohorted).
- "cohorted_discussions": list of discussions that should be cohorted. Any not specified in this list are not cohorted.
- "auto_cohort": Truthy.
- "auto_cohort_groups": ["group name 1", "group name 2", ...]
- If cohorted and auto_cohort is true, automatically put each student into a random group from the auto_cohort_groups list, creating the group if needed.
* TODO: there are others
### Grading policy file contents
TODO: This needs to be improved, but for now here's a sketch of how grading works:
* First we grade on individual problems. Correct and total are methods on CapaProblem.
`problem_score = (correct , total)`
* If a problem weight is in the xml, then re-weight the problem to be worth that many points
* Now we have all of the percents for all of the graded sections. This is the gradesheet that we pass to to a subclass of CourseGrader.
* A WeightedSubsectionsGrader contains several SingleSectionGraders and AssignmentFormatGraders. Each of those graders is run first before WeightedSubsectionsGrader computes the final grade.
- SingleSectionGrader (within a WeightedSubsectionsGrader) contains one section
`grader_percent = section_percent`
- AssignmentFormatGrader (within a WegithedSubsectionsGrader) contains multiple sections matching a certain format
* `display_name` - name that will appear when this content is displayed in the courseware. Useful for all tag types.
* `format` - subheading under display name -- currently only displayed for chapter sub-sections. Also used by the the grader to know how to process students assessments that the
section contains. New formats can be defined as a 'type' in the GRADER variable in course_settings.json. Optional. (TODO: double check this--what's the current behavior?)
* `hide_from_toc` -- If set to true for a chapter or chapter subsection, will hide that element from the courseware navigation accordion. This is useful if you'd like to link to the content directly instead (e.g. for tutorials)
* `ispublic` -- specify whether the course is public. You should be able to use start dates instead (?)
__Inherited:__
* `start` -- when this content should be shown to students. Note that anyone with staff access to the course will always see everything.
* `showanswer` - When to show answer. For 'attempted', will show answer after first attempt. Values: never, attempted, answered, closed. Default: closed. Optional.
* `graded` - Whether this section will count towards the students grade. "true" or "false". Defaults to "false".
* `rerandomize` - Randomize question on each attempt. Values: 'always' (students see a different version of the problem after each attempt to solve it)
'onreset' (randomize question when reset button is pressed by the student)
'never' (all students see the same version of the problem)
'per_student' (individual students see the same version of the problem each time the look at it, but that version is different from what other students see)
Default: 'always'. Optional.
* `due` - Due date for assignment. Assignment will be closed after that. Values: valid date. Default: none. Optional.
* attempts: Number of allowed attempts. Values: integer. Default: infinite. Optional.
* `graceperiod` - A default length of time that the problem is still accessible after the due date in the format "2 days 3 hours" or "1 day 15 minutes". Note, graceperiods are currently the easiest way to handle time zones. Due dates are all expressed in UCT.
* `xqa_key` -- for integration with Ike's content QA server. -- should typically be specified at the course level.
__Inheritance example:__
This is a sketch ("tue" is not a valid start date), that should help illustrate how metadata inheritance works.
<course start="tue">
<chap1> -- start tue
<problem> --- start tue
</chap1>
<chap2 start="wed"> -- start wed
<problem2 start="thu"> -- start thu
<problem3> -- start wed
</chap2>
</course>
## Specifying metadata in the xml file
Metadata can also live in the xml files, but anything defined in the policy file overrides anything in the xml. This is primarily for backwards compatibility, and you should probably not use both. If you do leave some metadata tags in the xml, you should be consistent (e.g. if `display_name`s stay in xml, they should all stay in xml. Note `display_name` should be specified in the problem xml definition itself, ie, <problem display_name="Title"> Problem Text </problem>, in file ProblemFoo.xml).
- note, some xml attributes are not metadata. e.g. in `<videoyoutube="xyz987293487293847"/>`, the `youtube` attribute specifies what video this is, and is logically part of the content, not the policy, so it should stay in the xml.
Another example policy file:
{
"course/2012": {
"graceperiod": "1 day",
"start": "2012-10-15T12:00",
"display_name": "Introduction to Computer Science I",
"xqa_key": "z1y4vdYcy0izkoPeihtPClDxmbY1ogDK"
},
"chapter/Week_0": {
"display_name": "Week 0"
},
"sequential/Pre-Course_Survey": {
"display_name": "Pre-Course Survey",
"format": "Survey"
}
}
## Deprecated formats
If you look at some older xml, you may see some tags or metadata attributes that aren't listed above. They are deprecated, and should not be used in new content. We include them here so that you can understand how old-format content works.
### Obsolete tags:
* `section` : this used to be necessary within chapters. Now, you can just use any standard tag inside a chapter, so use the container tag that makes the most sense for grouping content--e.g. `problemset`, `videosequence`, and just include content directly if it belongs inside a chapter (e.g. `html`, `video`, `problem`)
* There used to be special purpose tags that all basically did the same thing, and have been subsumed by `customtag`. The list is `videodev, book, slides, image, discuss`. Use `customtag` in new content. (e.g. instead of `<bookpage="12"/>`, use `<customtagimpl="book"page="12"/>`)
### Obsolete attributes
* `slug` -- old term for `url_name`. Use `url_name`
* `name` -- we didn't originally have a distinction between `url_name` and `display_name` -- this made content element ids fragile, so please use `url_name` as a stable unique identifier for the content, and `display_name` as the particular string you'd like to display for it.
# Static links
If your content links (e.g. in an html file) to `"static/blah/ponies.jpg"`, we will look for this...
* If your course dir has a `static/` subdirectory, we will look in `YOUR_COURSE_DIR/static/blah/ponies.jpg`. This is the prefered organization, as it does not expose anything except what's in `static/` to the world.
* If your course dir does not have a `static/` subdirectory, we will look in `YOUR_COURSE_DIR/blah/ponies.jpg`. This is the old organization, and requires that the web server allow access to everything in the couse dir. To switch to the new organization, move all your static content into a new `static/` dir (e.g. if you currently have things in `images/`, `css/`, and `special/`, create a dir called `static/`, and move `images/, css/, and special/` there).
Links that include `/course` will be rewritten to the root of your course in the courseware (e.g. `courses/{org}/{course}/{url_name}/` in the current url structure). This is useful for linking to the course wiki, for example.
# Tabs
If you want to customize the courseware tabs displayed for your course, specify a "tabs" list in the course-level policy. e.g.:
"tabs" : [
{"type": "courseware"}, # no name--always "Courseware" for consistency between courses
{"type": "course_info", "name": "Course Info"},
{"type": "external_link", "name": "My Discussion", "link": "http://www.mydiscussion.org/blah"},
{"type": "textbooks"} # generates one tab per textbook, taking names from the textbook titles
]
* If you specify any tabs, you must specify all tabs. They will appear in the order given.
* The first two tabs must have types `"courseware"` and `"course_info"`, in that order. Otherwise, we'll refuse to load the course.
* for static tabs, the url_slug will be the url that points to the tab. It can not be one of the existing courseware url types (even if those aren't used in your course). The static content will come from `tabs/{course_url_name}/{url_slug}.html`, or `tabs/{url_slug}.html` if that doesn't exist.
* An Instructor tab will be automatically added at the end for course staff users.
## Supported tab types:
* "courseware". No other parameters.
* "course_info". Parameter "name".
* "wiki". Parameter "name".
* "discussion". Parameter "name".
* "external_link". Parameters "name", "link".
* "textbooks". No parameters--generates tab names from book titles.
* "progress". Parameter "name".
* "static_tab". Parameters "name", 'url_slug'--will look for tab contents in
'tabs/{course_url_name}/{tab url_slug}.html'
* "staff_grading". No parameters. If specified, displays the staff grading tab for instructors.
# Tips for content developers
* We will be making better tools for managing policy files soon. In the meantime, you can add dummy definitions to make it easier to search and separate the file visually. For example, you could add:
before the week 1 material to make it easy to find in the file.
* Come up with a consistent pattern for url_names, so that it's easy to know where to look for any piece of content. It will also help to come up with a standard way of splitting your content files. As a point of departure, we suggest splitting chapters, sequences, html, and problems into separate files.
* Prefer the most "semantic" name for containers: e.g., use problemset rather than sequential for a problem set. That way, if we decide to display problem sets differently, we don't have to change the xml.
# Other file locations (info and about)
With different course runs, we may want different course info and about materials. This is now supported by putting files in as follows:
/
about/
foo.html -- shared default for all runs
url_name1/
foo.html -- version used for url_name1
bar.html -- bar for url_name1
url_name2/
bar.html -- bar for url_name2
-- url_name2 will use default foo.html
and the same works for the `info` directory.
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(Dev note: This file is generated from the mitx repo, in `doc/xml-format.md`. Please make edits there.)
