Strengths and limitations

Quantitative method
Quantitive data are pieces of information that can be counted and which are usually gathered by surveys from large numbers of respondents randomly selected for inclusion. Secondary data such as census data, government statistics, health system metrics, etc. are often included in quantitative research. Quantitative data is analysed using statistical methods. Quantitative approaches are best used to answer what, when and who questions and are not well suited to how and why questions.

Strengths Limitations
Findings can be generalised if selection process is well-designed and sample is representative of study population Related secondary data is sometimes not available or accessing available data is difficult/impossible
Relatively easy to analyse Difficult to understand context of a phenomenon
Data can be very consistent, precise and reliable Data may not be robust enough to explain complex issues


Qualitative method
Qualitative data are usually gathered by observation, interviews or focus groups, but may also be gathered from written documents and through case studies.  In qualitative research there is less emphasis on counting numbers of people who think or behave in certain ways and more emphasis on explaining why people think and behave in certain ways.  Participants in qualitative studies often involve smaller numbers of tools include and utilizes open-ended questionnaires interview guides.  This type of research is best used to answer how and why questions and is not well suited to generalisable what, when and who questions.

Strengths Limitations
Complement and refine quantitative data Findings usually cannot be generalised to the study population or community
Provide more detailed information to explain complex issues More difficult to analyse; don’t fit neatly in standard categories
Multiple methods for gathering data on sensitive subjects Data collection is usually time consuming
Data collection is usually cost efficient

Learn more about using quantitative and qualitative approaches in various study types in the next lesson.

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