The data you collect for an evaluation may come in a number of forms. It may be quantitative, including numbers from monitoring or collected through closed questions on questionnaires.
This information might have been collected at the end of a project or activity, or throughout.
Data can also come in the form of transcriptions of interviews or focus group discussions, open feedback, meeting minutes, photographic documentation of activities, even artworks created by participants.
Things you will need to consider, whatever kind of data you collect, include how you will ensure that the confidentiality, and maybe also the anonymity of respondents and participants will be ensured, and how you are going to avoid bias.
The way in which you design and administer forms and questionnaires or run interviews and focus groups can introduce bias and will need careful thought.
In addition, you will want to think about how to use sampling to make your evaluation encompass as wide a range of participants’ experiences as possible.