In order to obtain high quality data, sufficient time and attention need to be given to the data collection phase and its set up. Based on the research questions, the following aspects need to be considered:
What is the population of interest? What would be a representative sample of this population?
What is an appropriate sample size?
How should the sample be obtained? Are experimental planning, randomization or a specific sampling stage needed?
Is a questionnaire needed and how should it be designed?
Designing the data collection phase
Different approaches can be used to design a data collection phase, depending on the research field, population of interest and research objectives. Experimental planning consists in designing experiments in the most efficient way, randomization can be used to set up randomized controlled trials and sampling methods aim at drawing samples from a sampling frame.