This document provides guidance for field work on the usage of Ed-Fi descriptors.
What is an Ed-Fi descriptor?
Descriptors are the Ed-Fi data model elements that hold standardized enumerations - the "code sets" used to categorize data and power reporting and analytics.
- the academic subject for a course
- the grade level a student in enrolled in
- the type of accommodation a student was provided for an assessment
In Ed-Fi, each element that is populated by pre-defined code set is referred to as a "descriptor."
Which descriptors are most important for my organization to pay attention to?
There are over 160 descriptors in the core Ed-Fi data model and many more in domains currently under development and not yet part of the core model. Not all of them will be relevant to your organization's use of Ed-Fi. Generally, the descriptors that matter most to your organization initially will be those involved in data exchanges between systems, so will depend on the APIs your work is making use of.
A good first list to pay attention to are the descriptors that are required in an Ed-Fi API certification, as these must be present in a data exchange. By API, those descriptors are:
Core Student API (aka the Student Information Systems API) | Assessment Outcomes API | Finance API |
|---|---|---|
Why do Ed-Fi descriptor values have a URL in them?
If you look at a descriptor in a Ed-Fi defined data packet, you will see it has this format:
Do I have to use Ed-Fi-defined values?
The answer to this question is "no" but there may be reasons why you should try to use these values.
For starters, no one is forced to use the Ed-Fi values. The Ed-Fi technologies and specifications are open source and can be used however desired. Plus, the Ed-Fi Alliance and its community have endorsed the notion that there is no set of code values (for example, for grade level) that is "universally applicable" (see below for more information on this). By definition, this means that we need to expect that code sets will be localized.
However, just because variation will always exist and just because there is no "universally applicable" set of values for any concept, it does NOT follow that it is not helpful for us to adopt a common sets in some cases, and for the Alliance to encourage - sometimes strongly encourage - community members to adopt common values. When we act in common ways, then we can rely on each other, share resources, and interoperate with each other easier.
Said anther way: there may be pain or loss in mapping local values to Ed-Fi values, but that pain provides benefits in terms of interoperability.
In what ways does Ed-Fi encourage or enforce compliance with particular value sets?
First, as we noted above, any Ed-Fi descriptor set can be modified.
However, the Ed-Fi Alliance does make particular requirements for usage of values in its standards and certifications. In order to be judged to be compliant with that specification, a product may be required to show that it can adopt particular sets, generally (but not necessarily ones) defined by the Ed-Fi data standard.
My organization is thinking of modifying a particular descriptor set. Should I do that?
The following are not part of the formal Ed-Fi specifications, but are based on an analysis of community practice by the Alliance and provides some guidance with regards to where agencies and organizations are likely to find more value in staying within the Ed-Fi descriptor value sets.. There are 4 categorizations.
| Category | Definition | Examples |
|---|---|---|
| Standard | There is reason to value standardization highly, because there is great (but not perfect!) standardization within the community. There is reason to believe that with sufficient governance a "good enough for most use cases" set of values is possible. The recommended practice is to stay within this set if at all possible. It is very likely that the value set is mandated by a standard or certification. | GradeLevel |
| Modified | The community is mostly standardized, but exceptions and localization are not infrequent. For these descriptors, Ed-Fi will define list that mirrors the standardization seen in the community. The recommended practice is to map to / use all Ed-Fi values within this set when possible, but add local values when and where there is high value to doing so, but realizing that in so doing there may be sacrifices to interoperability. | AcademicSubject |
| Base | The community is somewhat standardized, or there are common, broadly-adopted vernacular classifications around the concept. Local usage may be completely at odds with the vernacular, and that is to be expected in some cases. For this set, Ed-Fi will generally define a "starter" set of values that mirror the most common vernacular. The recommended practice is to map to / use Ed-Fi values when applicable, but to also feel free to remove or avoid unnecessary Ed-Fi values. | |
| Customize | The option set values are highly localized in nearly all cases. For this set, Ed-Fi will generally define a "sample" set of values that illustrate a possible values, or not provide any Ed-Fi defined values at all. The recommended practice here is to add your own values. There should be no hard or reason to preserve any "default" Ed-Fi-defined values here. | GradingPeriod |
How do I create my own descriptors?
All code sets depend on a context; said another way, there is no such thing as a code set that will work for all contexts. While we may think of some categorizations as being universal – such as grade levels - there are always and will always be variations, somewhere. This is part of the natural variation of the education ecosystem.
However, because there are always possible variation does not mean that there is not value to encouraging (perhaps strongly in some cases) usage and community governance of some sets of values. if we all agree to use the same set of values for grade level, that can hep us a great deal to share resources. There may be loss in converting our values to those values, but the benefits may be worth it.