A question was raised in a meeting this week about evaluation priorities and how to determine them.  This reminded me that perhaps a discussion of formative and summative was needed as knowing about these roles of evaluation will help you answer your questions about priorities.

Michael Scriven coined the terms formative and summative evaluation in the late 1960s.  Applying these terms to the role evaluation plays in a program has been and continues to be a useful distinction for investigators.  Simply put, formative evaluation provides information for program improvement.  Summative evaluation provides information to assist decision makers in making judgments about a program, typically for adoption, continuation, or expansion.  Both are important.

When Extension professionals evaluate a program at the end of an training or other program, typically, they are gathering information for program improvement.  The data gathered after a program are for use by the program designers to help improve it.  Sometimes, Extension professionals gather outcome data at the end of a training or other program.  Here, information is gathered to help determine the effectiveness of the program.  These data are typically short term outcome data, and although they are impact data of a sort, they do not reflect the long term effectiveness of a program.  These data gathered to determine outcomes are summative.  In many cases, formative and summative are gathered at the same time.

Summative data are also gathered to reflect the intermediate and long term outcomes.  As Ellen Taylor-Powell points out when she talks about logic models, impacts are the social, economic, civic, and/or environmental consequences of a program and tend to be longer term.  I find calling these outcomes condition changes helps me keep in mind that they are the consequences or impacts of a program and are gathered using a summative form of evaluation.

So how do you know which to use when?  Ask yourself the following questions:

1. What is the purpose of the evaluation? Do you want to know if the program works or if the participants were satisfied?
2. What are the circumstances surrounding the program?Is the program in its early development or late development? Are the politics surrounding the program challenging?
   
3. What resources are available for the evaluation? So you have a lot of time or only a few weeks?  Do you have access to people to help you or are you on your own?
4. What accountability is required? Do you have to report about the effectiveness of a program or do you just have to offer it?
5. What knowledge generation is expected or desired? Do you need to generate scholarship or support for promotion and tenure?

Think of the answers to these questions as a decision tree as the answers to these questions will help you prioritize your evaluation.  Those answers will help you decide if you are going to conduct a formative evaluation, a summative evaluation, or include components of both in your evaluation.