Validity and Reliability in Visual Methods

Comment on Validity and Reliability in Visual Methods


Validity is the extent to which a method of research truly measures what it set out to and how accurate the results are (Golafshani 2003). Internal validity of a photo document requires: a considered selection of what to document, systematic and justified sampling and low reactivity from the subjects photographed. Validity considers not only the criteria used by a photographer to take a valid photo, but whether the criteria are employed consistently. The reliability of the data has to be proven before internal validity is achieved. Without reliable data, external validity would be discounted (Adelman 1998: 151).

Reliability is the extent to which a study can provide consistent results and an accurate representation of what is being studied. If results can be achieved again under similar circumstances then the research is considered reliable. Validity does not exist without reliability, validity has to be demonstrated sufficiently before reliability can be estimated (Golafshani 2003).

There are however a number of issues with these concepts. In visual methods the greatest threat to validity is not going down an unstable line of theorising, but having to account for photographic data that does not match the rules of sampling or data collection. One of the crucial problems of validating photos as evidence is to be able to account for the inclusion of particular context in the photograph (Adelman 1998: 152). Neither concept of validity or reliability is universal, many researchers in different fields have developed their own concepts of validity and reliability. Studies can also suffer from bias, and it is not unknown for researchers to affect the outcome of their data to validate their investigation. The involvement of the researcher’s perspectives can seriously reduce the validity of their hypothesis (Golafshani 2003).






LIST OF REFERENCES

Adelman, C. (1998) ‘Photocontext’. In Image-based Research: A Sourcebook for Qualitative Researchers. Ed. by Prosser, J. Abingdon: RoutledgeFalmer: 148-161

Golafshani, N. (2003) ‘Understanding Reliability and Validity in Qualitative Research’. The Qualitative Report [online] 8, (4) 597-607. Available from http://www.nova.edu/ssss/QR/QR8-4/golafshani.pdf [Accessed 5 April 2009]