Formative evaluation (which includes implementation and process evaluations) considers the success of project implementation, and ongoing project process and performance.  This type of evaluation examines the development of the project and may lead to changes in the way the project is structured and carried out. It is focused on learning as you carry out activities in order that better knowledge and understanding can lead to appropriate change in the way things are being done. Questions typically asked include:

• To what extent do the activities and strategies match those described in the project plan? If they do not match, are the changes in the activities justified and described?
• To what extent were the activities conducted according to the proposed timeline? By the appropriate people?
• To what extent are the actual costs of project implementation in line with initial budget expectations?
• To what extent are the participants moving toward the anticipated goals of the project?
• Which of the activities or strategies are aiding the participants to move toward the goals?
• What barriers were encountered? How and to what extent were they overcome?

Summative evaluation (also called outcome or impact evaluation) addresses the longer term outcomes or impacts of project activities. This type of evaluation looks at what a project has actually accomplished in terms of its stated goals. Summative evaluation questions include:

• To what extent did the project meet its overall goals?
• Was the project equally effective for all participants?
• What components were the most effective?
• What significant unintended impacts did the project have?
• Is the project replicable and transportable?

In both formative and summative evaluation, both quantitative data (data expressed in numbers) and qualitative data (data expressed in narratives or words) can be useful in a variety of different ways.

Source: National Science Foundation’s (NSF) Directorate for Education and Human Resources (EHR)