Table 1:

Examples of some items in the Template for Intervention Description and Replication checklist31 and their importance for placebo controls

Checklist item	Example of why this detail is important
Why (what is the rationale, theory or goal of the elements essential to the intervention)	To determine the extent to which actual placebos deviate from the ideal, we need to know what the placebo control is designed to control for. In a drug trial, this will typically be the patented chemical(s) in the formulation. For complex interventions, such as exercise and acupuncture, this can be more difficult but is nevertheless important to articulate.
What is in the placebo control The colour, size and shape of the placebo can have direct effects on the outcome. Procedures that involve additional liquids or food could influence the outcomes unless these are shared in control and experimental groups.	Lactose (a common placebo ingredient) is believed to have an additional benefit for some target ailments such as gastrointestinal disorders.32 Red, yellow and orange are associated with a stimulant effect, whereas blue and green are related to a tranquilizing effect.4 Unless the placebo control appears similar to the senses, the patient could identify it as a placebo, threatening the success of blinding, and excipients can also have an unanticipated effect (e.g. using olive oil).18 More invasive sham devices can have greater effects than oral formulations.7
Who delivered the placebo control Clinician style and communication manner can affect outcomes.	In general, clinicians who are women are perceived as more empathic than those who are men, and this can affect outcomes, especially if the type of provider is not similarly distributed between intervention and control groups.21,33
When and how much The number of placebo formulations and the type of placebo can affect outcomes.	Two tablets can have a greater effect than one.34 Large oral formulations seem to be associated with greater effects than with small ones.6