WHY IS STANDARDIZATION IMPORTANT?
Treatment fidelity refers to strategies used within an intervention study to monitor the implementation of the intervention to ensure that it is being delivered as intended. As discussed in Chapter 12, having a treatment fidelity plan enhances the reliability and validity of an intervention trial and is integral to the interpretation of study findings (Resnick et al., 2005). For example, if an investigator discovered after the completion of a trial that there was variation among the trial interventionists in the delivery of the intervention, it would be extremely difficult to interpret the findings of the study and understand if the outcomes were due to the treatment or to differences in interventionist behavior. Thus, in this case, we would learn very little about the impact of an intervention, which would be a waste of time, effort, and resources.
Standardization of the intervention protocol is a key element of treatment fidelity and has a significant impact on the internal validity of an intervention trial. It can also influence external validity. If, for example, differential inclusion/exclusion criteria were applied to study participants, it would be difficult to make statements about the generalizability of study outcomes. Standardization of the intervention protocol instills greater confidence that the intervention treatment was delivered consistently across participants as intended. This in turn reduces variability and potential biases, which results in greater confidence in the validity and reliability of the study outcomes. Standardization also enhances the ability of other investigators to replicate an intervention protocol, which is particularly important in multisite trials and in the implementation phase; the efficiency of a trial; and an investigator’s ability to disseminate findings that emanate from a study.
For example, in the Personal Reminder Information System Management (PRISM) trial (Czaja, Loewenstein, Schulz, Nair, & Perdomo, 2014), which was a multisite trial that investigated the impact of a specially designed software program on the social connectivity and well-being of older adults at risk for social isolation, each site had multiple interventionists who implemented the intervention protocol (e.g., training the participants on the use of the software). The training program for the interventionists was standardized in that all interventionists were trained similarly and certified by the Miami site. This helped to ensure consistency among the interventionists and also reduced training costs, especially during the course of the project when new interventionists were brought on board.