Improving External Validity May Jeopardize Internal Validity

External, Internal and Construct Validity

Introduction In research, validity refers to the degree to which findings are applicable in real-life situations. Essentially, if the findings are strongly valid, it implies that they have an excellent degree of applicability. In contrast, low validity implies that the survey is not applicable in real-life situations. The specific approach used during research has strong influence on validity. ...

Do pragmatic trials trade-off internal validity for external validity?

Trials can be described as being on a design spectrum between highly explanatory (roughly, ‘Can the intervention work?’) to highly pragmatic (‘Does the intervention work in routine care?’). A criticism levelled at trials that take a pragmatic approach is that they sacrifice internal validity for external validity, i.e. there is a trade-off to be made. Proponents of pragmatic trials argue that t...

Why internal validity is not prior to external validity

Internal and External Validity in Clinical Research

dvances in clinical psychology critically depend on methods researchers use for investigating the causal relationships among variables. Research questions commonly include issues about the putative mechanisms associated with various forms of psychopathology (e.g., do dysfunctional beliefs cause depression?) and questions about the effects of treatments (e.g., does cognitive therapy cause a grea...

Internal and external validity of cohort studies.

I participated with pleasure in discussions on 30 September 2011 in Warsaw during the ‘Diff erences in Health in the Polish population’ Conference, which aimed at critical assessment of fi rst baseline results from the PONS study, a pilot prospective cohort established in Poland. Th e PONS study results from the ‘Closing the Health Gap’ Report recommending an attempt to start building in Centra...