There are four main types of data and research methods: primary data, secondary data, qualitative data, and quantitative data. Primary data involves directly collecting information through surveys or questionnaires, while secondary data analyzes previously collected data from other sources. Qualitative data describes information in specific details rather than numbers, and explores topics in depth through interviews. Quantitative data expresses information numerically and can generalize findings to a whole population through statistically valid surveys, but has limited ability to probe answers. Each method has its own pros and cons regarding costs, accuracy, and level of detail obtained.