Research Methods: Developing your research design

Eira Patterson | View as single page | Feedback/Impact

How can validity and reliability be improved?

How can validity be improved?

The validity of the research findings are influenced by a range of different factors including choice of sample, researcher bias and design of the research tools. The table below compares the factors influencing validity within qualitative and quantitative research contexts (Cohen, et al., 2011 and Winter, 2000):

Qualitative research

Quantitative research

Researcher bias / objectivity / honesty

Appropriate statistical analysis of the data

Design of research tools

Design of research tools

Sample selection

Sample selection

The use of triangulation

Sample size

Validity should be viewed as a continuum, at is possible to improve the validity of the findings within a study, however 100% validity can never be achieved. A wide range of different forms of validity have been identified, which is beyond the scope of this Guide to explore in depth (see Cohen, et. al. 2011 for more detail).

The chosen methodology needs to be appropriate for the research questions being investigated and this will then impact on your choice of research methods. The design of the instruments used for data collection is critical in ensuring a high level of validity. For example it is important to be aware of the potential for researcher bias to impact on the design of the instruments. It is necessary to consider how effective the instruments will be in collecting data which answers the research questions and is representative of the sample.

It is also necessary to consider validity at stages in the research after the research design stage. At the implementation stage, when you begin to carry out the research in practice, it is necessary to consider ways to reduce the impact of the Hawthorne effect. Finally at the data analysis stage it is important to avoid researcher bias and to be rigorous in the analysis of the data (either through application of appropriate statistical approaches for quantitative data or careful coding of qualitative data).

How can reliability be improved?

In qualitative research, reliability can be evaluated through:

  • respondent validation, which can involve the researcher taking their interpretation of the data back to the individuals involved in the research and ask them to evaluate the extent to which it represents their interpretations and views;

  • exploration of inter-rater reliability by getting different researchers to interpret the same data.

In quantitative research, the level of reliability can evaluated be through:

  • calculation of the level of inter-rater agreement;

  • calculation of internal consistency, for example through having two different questions that have the same focus.