Simulated patient methodology as a “gold standard” in community pharmacy practice: Response to criticism

Abstract

The simulated patient methodology (SPM) is considered the “gold standard” as covert participatory observation. SPM is attracting increasing interest for the investigation of community pharmacy practice; however, there is criticism that SPM can only show a small picture of everyday pharmacy practice and therefore has limited external validity. On the one hand, a certain design and application of the SPM goes hand in hand with an increase in external validity. Even if, on the other hand, this occurs at the expense of internal validity due to the trade-off situation, the justified criticism of the SPM for investigating community pharmacy practice can be countered.

Key Words: Simulated patient methodology; Community pharmacy; Gold standard; Covert participatory observation; Internal validity; External validity

Core Tip: The simulated patient methodology (SPM) is considered the “gold standard” as covert participatory observation. SPM is attracting increasing interest for the investigation of community pharmacy practice. However, there is criticism that SPM can only show a small picture of everyday pharmacy practice. However, if the SPM is designed and applied in a certain way, this criticism can be countered.

TO THE EDITOR

The simulated patient methodology (SPM) is a participatory observation in which simulated patients (SPs) covertly contact a healthcare facility and simulate participation in a seemingly real service process based on a predetermined scenario[1]. In both older and more recent international literature, the SPM is considered the “gold standard”[2,3], in part due to its high internal validity[3]. In addition to application settings such as health insurance companies, hospitals, and primary care, SPM also plays a major role in community pharmacies[4]. There has been an increasing number of SPM studies on pharmacy practice[4,5], such that not only worldwide reviews[4,5] but also reviews on selected regions[6] and even individual countries[7] have been published. In fact, other review articles - in addition to those already compiled on visits[4] as a “traditional”[8] form in the CP setting - are planned for other forms of SPM such as calls[9]. Finally, a checklist for reporting research using SPM (CRiSP) was recently published, based on a Delphi study focusing on pharmacy[10].

In addition to the increasing interest in SPM to investigate CP practice, there is also criticism that the SPM can only represent a small picture of everyday pharmacy practice[11] and therefore has limited external validity[3]. One of the reasons for this critique is that in a single contact with a CP, the service process of only one specific pharmacy employee can be observed and evaluated at a given time, whereby only one SP with certain characteristics can participate. Furthermore, the SP can either make a purchase for themselves (self-purchase scenario) or for a third party (purchase for a third-party scenario)[12]. Finally, the SP's demand may only include a specific product (e.g., aspirin), condition (e.g., migraine), or symptom (e.g., headache) based on a corresponding simulated scenario[3]. Conversely, in everyday pharmacy practice, different pharmacy employees and customers as well as different scenario combinations can in principle be mapped at different times; however, this was not reproduced in the SPM studies examined in the reviews[4,5], with a few exceptions[13].

To provide as comprehensive a picture as possible of everyday pharmacy practice, a certain design and application of the SPM are required. For example, a CP should be contacted several times and at different times to increase the probability of being able to observe and evaluate several pharmacy employees. SPs with different characteristics (e.g., 20/40/60-year-old man/woman with/without migration background, etc.) should be used in coordination with the scenario (e.g., an 80-year-old man's request for emergency contraception does not correspond to everyday pharmacy practice) to account for the diversity of customers. Finally, several scenario combinations should be used. Accordingly, an SPM study should include scenarios for self-purchase and purchase for a third party and (ideally) at least the conditions or symptoms most frequently responsible for self-medication, and in relation to these, the products most commonly requested or recommended in guidelines. On the one hand, such a design and application of the SPM goes hand in hand with an increase in external validity. Even if, on the other hand, this is at the expense of internal validity due to the trade-off situation and is also associated with considerable personnel and organizational effort, the justified criticism of the SPM for investigating CP practice can be countered.