Primary data is gathered directly from the affected population. It is collected by assessment teams through fieldwork, most often through face-to-face interviews T.23 or discussions with members of the affected community T.14. It may also be gathered through other methods including Community Mapping T.7, phone interviews, social media and email exchange T.44, radio communication T.38 and direct Observation T.28. For hygiene promotion (HP) purposes, primary data collection is an important way to engage with the population (chapter  E ) at an early stage of the programme design. It also ensures that the project is inclusive and relevant at the local level and that the assessment builds a holistic and accurate picture of the affected population. 

Secondary data has usually been collected before the primary data and has undergone at least one layer of analysis before its inclusion in the assessment. Secondary data may be in the form of published research, media reports and/or data that has been cleaned, analysed and collected for purposes other than the assessment (such as academic research or agency or sector specific monitoring reports). 

Both primary and secondary data can be collected and analysed using quantitative or qualitative assessment methods.

Quantitative methods collect numerical data through surveys or by working with pre-existing statistical data. Findings can either be applied across groups of people, to explain a particular phenomenon, or to describe a characteristic. They are useful during the assessment phase as they measure coverage, knowledge and practices. Data collection methods may include structured Observation T.28, surveys and checklists (T.24 and A.8), polls, telephone or face-to-face Interviews T.23. Analysis of quantitative methods requires some knowledge of statistics but software is available to support this. 

Qualitative methods are useful during the assessment phase to collect and analyse data that reveals attitudes, perceptions or intentions e.g. to determine people’s perception of risk or the barriers to healthy behaviours (chapter  B ). 

Qualitative data is what people describe or illustrate (through photographs for example). It is usually analysed by identifying common themes and issues of concern and grouping them to draw broader conclusions. The results of qualitative data analysis should not be translated into percentages or numerical data without a clear explanation (e.g. although numbers can be obtained using Pocket Chart Voting T.31, they cannot be used to represent the rest of the population). The use of more general terms can help to indicate, for example, if the majority or only a few people expressed a particular view. 

Triangulation compares several different data sources and methods to cross check and confirm findings. For example, teachers, community health workers, children and parents’ perspectives on HP at school can be compared to prevent assumptions from being made. Triangulation can strengthen conclusions or identify areas for further work.