What is the difference between process, outcome and impact evaluations?
A process evaluation looks at the actual development and implementation of a particular program. It establishes whether you’ve hit quantifiable targets and implemented strategies as planned. It’s typically done at the end of the project and it looks at the program from start to finish, assessing cause-and-effect relationships between the program components and outcomes. This type of evaluation can be very useful in determining whether a program should be continued, expanded upon, refined or eliminated.
While they can be done separately, outcome and impact evaluations are also important additions to a process evaluation. Outcome evaluation measures the change that has occurred as a result of a program. For example, your process evaluation might confirm that 200 people have completed your skills-training program. An outcome evaluation would tell you how many of those demonstrated increased confidence, changed behaviors, found jobs because of the new skills, etc.
An impact evaluation looks at the long-term, deeper changes that have resulted from that program. This type of evaluation could, for example, suggest that the changes to your skills-training participants’ lives continued over time and perhaps transferred across generations.
While the outcome evaluation tells us what kind of change has occurred, an impact evaluation paints a picture as to how a program might have affected participants’ lives on a broader scale.
It’s important to note that certain types of evaluation are more involved than others. For example, while certain outcomes can be easily and reliably measured, true impact measurement is a much trickier business. In its truest sense, impact measurement often involves using an independent evaluator, establishing control groups, and measuring changes over extended periods of time. This can be extremely costly, and reliable results may take years to emerge (depending on the nature of the program, of course).
We raise these issues not to sway you from impact evaluation. Rather, we want to paint a complete-enough picture to encourage you to invest the resources when the time is right. In other words, if your program’s content is potentially replicable and highly impactful – an HIV prevention program or a curriculum intended to connect young adults to good jobs, for example – then it’s probably worth it to find the necessary funding to have it evaluated at full scale.