Both methods have different advantages and disadvantages. In many cases, a combination of the two is most sensible.

The application of qualitative methods is recommended

• when little knowledge of the research subject or context is available
• to validate previously made decisions after the fact
• to strengthen interpretations of quantitative data for the development of optimal quantitative questionnaires
  

Qualitative Analyses

• can be developed relatively quickly, but require a lot of time and effort to be carried out and analyzed
• are characterized by their openness and flexibility
• contain a high level of authenticity and consideration of culturally appropriate styles
• can be “playful” and so are less stressful for children
• can be carried out with a relatively small sample
• are suited to exploration, hypothesis formation and the discovery of new facts

The application of quantitative methods is recommended

• when representative and reliable findings are essential
• when comparisons at the group level (aggregate level) are being made
• when causal relationships are to be identified
• when statistical correlations need to be determined
  

Quantitative Analyses

• are efficiently carried out and evaluated, but difficult to construct
• deliver exact quantifiable results
• are characterized by a high standardization, objectivity and comparability
• allow for generalization of the total examined population
• need relatively large samples
• are suited to testing hypotheses