You need data to reinforce your assumptions and create value in the minds of your consumers, stakeholders, and funders. This perception of value is subjective; what your community values this year may be quite different next year. You must collect and analyze data to fully understand market needs. Marketing research works to provide the facts and direction that stakeholders and funders need to continue support.
Effective marketing research is systemic and dynamic and covers a wide range of activities. It may include trend analysis, which deals specifically with the gathering of information about a market's size and direction. It often includes processes like outcomes measurement, which works to assess your programs and guage success. It can also include a community engagement piece, that works to understand the perception of need in your consumers.
Every situation is different, but a marketing research project follows a general systematic process: 1) Problem definition, 2) research design, 3) data type & source identification, 4) data collection methodology, 5) data sampling 6) data collection, and 7) data analysis. This process can be applied to a variety of marketing problems.