Formal and Informal Assessments

In special education, formal assessments require parental consent and are done for initial IEP and triennial reports. Informal assessments are the classroom assessments that teachers do for progress monitoring and for writing the present levels and goal sections of IEPs. Read on to learn more about the differences between the two types of assessments and when each is useful!

Formal Assessments

Formal assessments are the assessments discussed in special education law, the type of assessments used to determine eligibility for special education. 

Formal assessments refer to norm referenced tests. These are tests where students’ scores are compared the scores of other students of the same age, typically on a normal distribution. Rather than telling you about what content a student does or does not know, a normal referenced test will tell you whether a student is in the average range (90-110), in the high average range (111-100), in the low average range (80-89), or the low range (70-79) and so on.


Formal assessments are a common part of qualifying process for special education and for related services. Some of the ones you might have seen are:

  • IQ tests like the Stanford-Binet test
  • Wechler test

For academic achievement, the two most common formal assessments are the Woodock-Johnson IV and the Kaufman Test of Educational Achievement. Both include sub-tests in reading, writing, and mathematics and provide standardized scores that tell you how a student’s performance on the test compares to the performance of other students the same age. 

Many of the sub-tests on the WJ and Kaufman are similar to classroom assessments in content. For example, the WJ IV has a sub-test for word problems called the applied math subtest and another for decoding called the letter word recognition subtest. The difference is that the tests go all the way from PreK through end of high school (a way wider range than you use in a normal assessment!) and that instead of getting information on what a student knows and doesn’t know (can they read CVC words? Words with long vowels?) you instead get a scaled score.

Note that there are no specific formal assessments in special education for just one subject, like reading. Instead the tests used are batteries and students are assessed across reading, writing, and mathematics.

To be valid, norm referenced tests have to have been tested on similar students. For example, if your student is an English Language Learner, formal assessment scores are only relevant on them if the test was tested on other ELLs. Furthermore, norm referenced test scores are only valid if, among many other things they are in the child’s primary language.

If any of the many conditions for validity are not met then the formal assessment is invalid and cannot be used in a special education assessment. That is why districts will often have specially trained staff to administer Spanish language assessments or choose not to do formal assessments. If you have read any history of eugenics in the United States, you know how badly formal assessments can be abused– which is why there are so many rules.

The federal law for special education outlines specific rules that have to be followed for a norm referenced, or formal, assessment, to be valid. These are that the tests: 

(i) Are selected and administered so as not to be discriminatory on a racial or cultural basis;
(ii) Are provided and administered in the child’s native language or other mode of communication and in the form most likely to yield accurate information on what the child knows and can do academically, developmentally, and functionally, unless it is clearly not feasible to so provide or administer;
(iii) Are used for the purposes for which the assessments or measures are valid and reliable;
(iv) Are administered by trained and knowledgeable personnel; and
(v) Are administered in accordance with any instructions provided by the producer of the assessments.

In many districts, special education teachers do no formal assessments. They are strictly done by school psychologists or other trained staff members. In many other districts, teachers are trained on and asked to do the Woodcock Johnson-IV or a similar academic norm referenced test. In those districts, teachers are responsible for administering the test, scoring it, and writing up a report on their results. Note that the WJ-IV and similar tests give teachers an automated “report” based on the student’s performance. This is gibberish and I highly recommend never giving it directly to parents. Instead, teachers can create their own template with explanations of the jargon and then copy and paste in the relevant sections from the automated report. 

Formal assessments are done for initial IEPs, triennial IEPs, an for interim IEPs if a student is being assessed for a related service. Special education teachers only do them for initial and triennial IEPs. For those, teachers are required to write a full annual IEP, which has the results of informal assessments, along with an academic assessment report which has the results of the formal assessments as well as, hopefully, the informal assessments that they did. [It is a pretty lousy report if it just has the mumbo jumbo that comes from the WJ-IV– parents want actual interpretable information as well]

It is really hard to emphasize how badly our country has bungled formal assessments in our history. We have administered invalid assessments in a discriminatory fashion and used their results to sterilize people, among other evils. As a result, the law is written to lay out clear guard rails around formal assessments. First, parents have to be informed of and consent to any formal assessment being done on their child. Second, the assessments have to be done properly. Third, parents can contest the results of formal assessments by not signing the IEP or by requesting their own assessments. 

Informal Assessments

Informal assessments are absolutely everything else. Weirdly, even state testing in the context of special education counts as an informal assessment. If the results are not scored on a normal distribution and it isn’t an individually administered test like the WJ-IV, it counts as an informal assessment. 

On your IEPs, you are likely to draw on many different informal assessments. These might include:

  • Benchmark testing results
  • State test scores
  • Classroom test scores
  • Work samples
  • Results from an informal assessment packet (like in the IEP Success Kit sold here!)
  • Writing samples
  • Classroom observations including of how often a student raises their hand, calls out, gets out of their seat, leaves the classroom, turns in homework, puts their head down in class, and so on
  • Insights from conversations with other teachers of the student

There is no formal measure of validity of an informal assessment. The goal is for you to form a holistic picture of the student’s baseline skills by drawing on as many data sources as possible. In research, we talk about the credibility of data. You need to make a credible case about a student’s performance by drawing on as many pieces of information as possible (which is called triangulation).

Informal assessments are all you! I strongly recommend talking to, getting work samples from, and getting data from general education teachers who work with your student but ultimately, you are the one who does the informal assessments and, in most districts, writes the IEP that comes from them. 

You do informal assessments for annual, initial, and triennial IEPs. Even if there are formal assessments for those meetings, you still have to do the informal assessments because they are what you use to write the Present Levels of Performance (also known as PLOP or PLAAFP) and the goals.

These aren’t formal and so parents don’t have rights over the assessments. Classroom teachers do assessments every day whether through quizzes or checking students’ work– informal assessments are considered part of the daily functioning of schools and so are not covered by assessment plans. That said, parents can still dispute the IEP that comes from the assessments– they just don’t provide consent for the assessments.

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