Theoretical concepts help us comprehend and explain data, such as to identify patterns or trends. The use of theories can aid in the design and conduct of an evaluation, such as when deciding on what kinds of data to collect and how it should be collected, and who should participate in the evaluation.
It is important to conduct an analysis of theories when evaluating data in order to ensure that results are valid and accurate. This can be accomplished by examining the assumptions behind of an evaluation or by comparing the results with other studies or models. It is also useful to verify the research question and the data collection methods.
The data can be collected via surveys, questionnaires or tests of statistical significance. measuring changes in a variable across time or between groups). The most common quantitative techniques comprise descriptive statistics such as mean and standard error, that summarize data by group or and inferential tests such as parametric and nonparametric tests that provide predictions about the whole population based on the data of the sample and meta analysis that compares the results of several independent studies.
Qualitative data often takes the form of textual documents, such as elicited texts (written specifically for the research, such as food diaries) or extant texts (such as meeting minutes or policy documents), or field notes produced during participant-observation or while conducting interviews and focus groups. This kind of data requires a distinct type of analysis, one which is more inductive than deductive. This is referred to as grounded theory and its main purpose is to develop new theories from the data by constantly interchanging between the processes of gathering and analysis.