In general, VALIDITY is an indication of how sound your research is. More specifically, validity applies to both the design and the methods of your research. Validity in data collection means that your findings truly represent the phenomenon you are claiming to measure. Valid claims are solid claims.

Validity is one of the main concerns with research. "Any research can be affected by different kinds of factors which, while extraneous to the concerns of the research, can invalidate the findings" (Seliger & Shohamy 1989, 95). Controlling all possible factors that threaten the research's validity is a primary responsibility of every good researcher.

INTERNAL VALIDITY is affected by flaws within the study itself such as not controlling some of the major variables (a design problem), or problems with the research instrument (a data collection problem).

"Findings can be said to be internally invalid because they may have been affected by factors other than those thought to have caused them, or because the interpretation of the data by the researcher is not clearly supportable" (Seliger & Shohamy 1989, 95).

Here are some factors which affect internal validity:

EXTERNAL VALIDITY is the extent to which you can generalize your findings to a larger group or other contexts. If your research lacks external validity, the findings cannot be applied to contexts other than the one in which you carried out your research. For example, if the subjects are all males from one ethnic group, your findings might not apply to females or other ethnic groups. Or, if you conducted your research in a highly controlled laboratory envoronment, your findings may not faithfully represent what might happen in the real world.

"Findings can be said to be externally invalid because [they] cannot be extended or applied to contexts outside those in which the research took place" (Seliger & Shohamy 1989, 95).

Here are seven important factors affect external validity: