It being September, I had quite a few good conversations about diagnostic assessments this week. Quite a few years ago, the practice with diagnostic assessments was to give students a task that was similar (or exact) to the summative assessment. The reasoning behind this was that you could then demonstrate growth for each student. You were sure that you were teaching them something. You were able to measure academic achievement. And while these are all good teaching practices (you want to teach them something and you want to be sure that you have) there were problems with this type of diagnostic assessment:

- Teachers said that they already knew the kids didn`t know X because they hadn`t taught it yet. This is certainly true for some subjects such as teaching Pythagorean Theorem for the first time or the War of 1812. Why would we really expect most of our students to already know that?
- Students hated these assessments because they usually didn’t do well. I wouldn’t want to do something that made me feel dumb no matter how many reassuring things the teacher said.
- Teachers didn’t really use these assessments. It told them something they already knew. They felt they were doing a lot of marking for no increase in understanding about their students.

The purpose of diagnostic assessment is to discover the entry points for students. We do want to know what knowledge the students are bringing to the table when we embark upon a new unit/learning cycle. It is important to realize that all students bring some knowledge with them. Good teachers identify this knowledge and understand how it fits into the content they are about to teach.

We were talking this week about teaching integers in grade 8. There is no reason to expect that very many of our students already know how to multiply and divide integers. The few that may already know this will identify themselves early on. However, it is useful for the teacher to know what the students do remember about integers. Therefore, the diagnostic assessment will help the teacher to identify how many students remember how to place integers on a number line, how many remember how to add and subtract integers, and most importantly for multiplication and division, how many remember how to create zero pairs (and now all you non-math people are thinking you should go back to grade 8).

Let’s suppose I was teaching grade 2 math and know that I need to teach students to add and subtract two digit numbers with and without regrouping. Some of my students may have already been taught the formal algorithm by their parents. Most won’t. Giving a test on this is only going to tell me that most students can’t do it. But, I do want to know other things: who has one-to-one correspondence, who knows their facts, or has strategies to figure them out, to 20, which kinds of manipulatives are the students comfortable with (block ten, open number line, hundreds boards), who is able to represent numbers in tens and ones). Once I know those things I am in a better position to move students forward. I cannot assume that all students are bringing the same mathematical knowledge to the table, but all of them are bringing something.

Diagnostic assessment needs to be fair and get you the information you need. Look carefully at the assessment tool you are using and make sure that it is designed so that students will be successful if they can. For example, we were looking at a commerical reading assessment and recognized that on one question most students could probably answer it but that the terminology was not familiar. So, we rewrote the question and changed the wording. On another question, rewriting it with a graphic organizer would allow more students to be successful. Diagnostic assessment is worthless if the student knew the answer but the question was unclear. As the teacher you may then think that the student doesn`t know something that he or she really does.

So if you rethink the concept of diagnostic assessment as determining the entry points for learning, you may find it a more useful exercise. Many times it doesn’t even need to be a formal assessment. In writing, just ask the students to write something. In science you could have the students do an experiment and see how they go about organizing themselves to complete it—you now have some information on their approach to the scientific method. In math, you may simply wish to have students solve some problems on the little whiteboards and show you their answers.

The goal of diagnostic assessment is to inform your teaching. In order to help students make connections between what they already know and what you hope to teach next, you need to know their starting points. And you have to start at *their* starting points. Once I have determined the entry points for my students in writing, that is going to determine which mini-lessons I can do as a whole group (most of my students will benefit), but more importantly, which lessons I will need to do with specific small groups of students.