testing validity and reliability in quantitative research

If the results obtained do not show consistency, then the tool can be considered unreliable. This is used to assess the reliability of tools in situations that remain constant over a period of time. Test-retest reliability involves assessment of reliability on two separate occasions then comparing the results. Forms of reliability include test-retest reliability, inter-rater reliability, inter-item reliability, and cross-test reliability. This is because the error is consistently reflected in all the values obtained. For example, a tape measure that produces a similar error in all measurements can be said to be reliable. Reliability can also be defined as the degree to which a tool of measurement can reproduce particular results. If the results obtained using a particular tool are consistent, then the tool can be said to be reliable. Reliability refers to the ability of a tool to produce consistent results (Ellis, Harley & Walsh, 2010). This tool requires variables that are associated with refined theoretical concepts. Theoretical validity assesses the degree to which agrees with basic theories. External validity can be classified into concurrent external validity and predictive external validity. If different results are obtained, then one of the tools is invalid.Įxternal validity tests the relationship between tools. If similar results are obtained, then the tools can be considered valid. However, face validity must be combined with others when assessing validity.Ĭomparative validity is an assessment tool that compares two or more tools of measurement. If at a glance, a tool appears to measure a variable accurately, then it can be considered valid.

Face validity is an assessment method based on the appearance of the measuring tool.

Testing validity and reliability in quantitative research