Research.
Innovation. Impact.

Scabies is a highly contagious parasitic skin disease and a recognised neglected tropical disease with substantial global burden. Permethrin and ivermectin are widely used treatments, yet uncertainty remains regarding their comparative effectiveness.

To systematically evaluate and compare the effectiveness of ivermectin versus permethrin for the treatment of scabies in humans.

Seven randomized controlled trials involving 1,216 participants were analyzed. Compared with permethrin, ivermectin was associated with a lower probability of clinical cure at final follow-up (RR = 0.93, 95% CI 0.86–0.99) and a higher risk of treatment failure (RR = 1.52, 95% CI 1.06–2.20).

Topical permethrin demonstrates a modest but clinically relevant advantage over ivermectin in achieving clinical cure and reducing treatment failure. Ivermectin remains a useful alternative where topical therapy is unsuitable, but optimized dosing regimens are essential.

Health research has traditionally privileged highly controlled study designs to maximise internal validity, yet such approaches often struggle to inform decision-making in complex, real-world settings.

To provide a design-oriented framework for selecting study designs that balance scientific rigor with pragmatic relevance across health systems.

The review demonstrates that study designs occupy positions along a rigor–pragmatism continuum rather than discrete hierarchies. Hybrid, pragmatic, and observational designs enhance relevance and policy utility when rigorously applied.

Balancing rigor and pragmatism through context-sensitive design selection can generate more usable evidence, strengthen policy impact, and improve population health outcomes.