Planning study design & methodology

study-design-metholodgy As good architectural design is must to build a marvelous house, similarly a strong study design/methodology is prerequisite for generating reliable and accurate evidence.

Ergonomics of study design & methodology necessitate maximum a priori planning and contemplation so that future study results are robust and generalizable.

Type of study designs (cross sectional or longitudinal, prospective or retrospective, observational or interventional and case-control or cohort), target population, inclusion and exclusion criteria of subject selection and their allocation are key bottlenecks which invariably confront a novice researcher. Multi-stage surveys or randomized controlled trials need meticulous planning and latter can be vexing for beginners or even experienced researchers who are busy in multiplicity of duties/responsibilities.

For example, researcher is aiming to test the efficacy of a newer teaching intervention over conventional teaching to improve mathematical scoring of middle school students. Randomized controlled trial (RCT) seems an ideal study design for aforementioned objective. However, simple RCT poses a vexing problem: How to randomize students in same class to two different teaching methods? In such setting, best option is to plan a cluster RCT where instead of individual students, classes are randomly allocated into one of the two teaching methods. Suppose there were 40 different sections of middle school students studying from class 6th to class 8th standard. Using cluster RCT design, 20 sections may be randomized to newer teaching invention and 20 class sections may be allocated to standard teaching.