Diagnostic Assessments

Determining prior knowledge to effectively teach students.

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The importance of diagnostic assessments

Assessments used before instruction are called diagnostic assessments. Students begin your course with prior knowledge, using past experiences to actively make meaning of new experiences in your course (see Constructivism). Assumptions about what students already know, or “should” know are built into course design and may be incorrect. Therefore, determining what students know, before teaching a topic, can help improve teaching in two ways:

  • Effectiveness: Understanding students' prior knowledge allows you to begin teaching students at an appropriate starting point as well as providing instruction and scaffolding within students’ Zone of Proximal Development. 
  • Misconceptions: If students have misconceptions about a topic, these will prevent students from building correct understandings of new content. Therefore, it is best to determine common misconceptions and their prevalence before teaching a topic, ensuring that incorrect prior knowledge is addressed. 

Choosing diagnostic assessments

While we will focus on conceptual inventories (assessments that check for student understanding), often, current conceptual inventories may not exist or cover content that you want to assess. Consider the following steps for creating your own measure:

  1. Content: Determine what pre-existing content, knowledge or abilities students may need for your course, or that you assume they will know or have encountered.
  2. Instrument: Creating a rigorous assessment of actual student knowledge is time consuming and beyond the scope of this page. Given time constraints for both test creation and delivery, a feasible diagnostic assessment will focus on student self-assessment. This can be done through asking students either yes/no questions of whether they understand or have encountered a topic, or rating on a scale how familiar or confident they are with a topic. Using close ended questions will automate analysis, though you may consider including open ended questions asking about content students find difficult or have struggled with in the past.
  3. Delivery: Automating this assessment can be very helpful and provide valuable feedback. It can be created as a test in UB Learns or by using other survey software such as Poll Anywhere, Google Survey, or Survey Monkey.

Creating your own diagnostic assessment is not as rigorous as a previously validated or tested conceptual inventory, but it is a feasible way to gauge each new group of students.

Conceptual Inventories

Conceptual Inventories (CIs) are designed to identify critical, common misconceptions and content knowledge among students (see Figure 1 below). These can be administered in large lectures and tend to be multiple choice quizzes or tests, with answers based on the more common misunderstandings about a topic. CIs can be administered again after misconceptions have been addressed to determine whether there has been conceptual change.

A list of CIs by discipline is provided below. Many of the CIs are already available for you to use, while others may require permission from the author before using.

It is important to understand that CIs do not include all the possible misconceptions or content knowledge that students may have about a topic. In addition, students can answer correctly in the CI without understanding why it is so. It is recommended to use other formative assessments in conjunction with CIs.

Using diagnostic assessments

If you want to use a diagnostic assessment in your course, consider the following:

  • Which topics have been difficult for students in the past because of prior knowledge issues?
  • Do you plan on assessing all topics at the beginning of the course, or each topic before they are taught?
  • Do you have a plan for how to approach topics that involve concepts students find difficult to learn? See Misconceptions.

Next steps

When you are done choosing or creating diagnostic assessments continue:

or move on to: