Research time horizons refers to the duration over which a study is conducted and data is collected. As a researcher, you need to think about the time horizons in research design as it can influence the type of data gathered and the research questions.
Cross-Sectional Design
Cross-sectional designs can use qualitative and quantitative research and they measure an aspect or behaviour of many groups or individuals at a single point in time.
Longitudinal Design
Longitudinal designs can also use qualitative and quantitative research but they study events and behaviours using concentrated samples over a longer period.
The approach one chooses is usually determined by your research question, your epistemological and ontological stances, and your skills or ability to utilise a certain approach.
Whatever choice you make, make sure to justify it, and try to compensate the limitations where necessary.
Related: Validity and reliability of a research study.
Related: Understanding the Research Process.
