Table 1.
Select Key Terms Used in the Multiphase Optimization Strategy (MOST) and Factorial Trial Design
| Term | Definition |
|---|---|
| Component | Any part of an intervention that can be separated out for study |
| Continual optimization principle | A guiding axiom in MOST where optimization is an iterative process toward a continuously improved intervention |
| Constraint | A restriction (time, money, participant burden, personnel, equipment, or other resources) that may limit the implementation of the intervention |
| Economy | Management or extent to which an intervention produces positive outcomes and is implemented without exceeding resource budget (money, time, or other health-care services/products) |
| Effectiveness | Determination that a treatment overall improves outcomes within a real-world setting |
| Efficiency | Extent to which the intervention improves outcomes with judicious use of health-care resources |
| Evaluation | Stage of the MOST framework following Optimization which aims to evaluate the effectiveness of the optimization intervention through an RCT |
| Factor | Independent variable in a factorial trial |
| Factorial experiments | An experimental design where the investigator manipulates factors (in MOST, intervention components) with differing levels at the same time resulting in multiple experimental conditions allowing for evaluation of main and interaction effects |
| Level | A discrete amount or presence of a factor in a factorial trial, often notated as a quantity (# of sessions) or presence/absence of an intervention element (Yes vs No text message reminders) |
| Multiphase Optimization Strategy (MOST) | A framework for preparing, optimizing, and evaluating multicomponent interventions making the best use of available resources. MOST is not a clinical trial design |
| Optimization | The process of identifying a multicomponent behavioral or biobehavioral intervention that provides the best expected outcome obtainable within key constraints imposed by the need for effectiveness, efficiency, economy, and/or scalability |
| Optimization criterion | A function of best expected outcome and key constraints (time, money, participant burden, and so forth) used to selection of intervention components and levels for inclusion in the optimized intervention |
| Resource management principle | A guiding axiom in MOST stipulating that investigators effectively and efficiently balance available resources in quest for scientific information |
| Scalability | The extent to which an evaluated, optimized intervention can be implemented without adjustment |