Table 1.

Advantages and disadvantages of empirical approaches for evaluating behavioral intervention dose

Purpose	Approach	Advantages	Disadvantages
Identify and narrow the universe of dose values	Retrospective analysis of data from completed RCT(s)	Provides quantitative evaluation of dose–response relationship Permits identification of cases for post hoc analyses (e.g., qualitative interviews of participants who were not adherent to the protocol) to inform future studies Comparison of intended and actual dose can be informative Permits evaluation of moderators of dose–response relationship via meta-regression	No randomization Reverse causation: positive dose–response relationship may indicate that participants improved because they received more intervention OR that they participated more because they improved Heterogeneity in control groups and interventions can obscure inferences
	Assessment of perceived optimal intervention dose via prospective survey or interview of key stakeholders	Involves multiple stakeholders, including patients, providers, operations partners, and administrators Evaluates perceived feasibility, acceptability, efficacy, or effectiveness of proposed doses Includes open- or close-ended questions Assesses broad range of issues efficiently	No randomization Stakeholder ideas may have little to do with efficacy or effectiveness Feedback from various stakeholders may be inconsistent
	Assessment of target patient behavior via prospective, longitudinal, observational studies	Determine how frequently unwanted thoughts, feelings, and behaviors occur (e.g., missed medication doses) Examine long-term change or short-term variability in behaviors	No randomization Selection bias Attrition Time burden
Validate expectation of optimal dose	Early-phase nonrandomized methods	Small sample size Strong alternative when randomization is not feasible Adaptive Precise and provides confidence intervals around optimal dose Considers both minimally effective dose and maximally tolerated dose	No randomization Statistical complexity Scant evidence supporting its use for behavioral interventions
	Randomized designs	Maximizes internal validity Examines interactions between dose parameters or dose parameters and other intervention components If more than one dose is efficacious, can distinguish optimal dose based on resources required Can evaluate sequences of dosing schedules	May be resource intensive and difficult to obtain funding May take several iterations until an optimal dose is identified May not be adaptive