CONTROLLED HUMAN EXPOSURE:

Studies should clearly describe the primary and any secondary objectives of the study, or specific hypotheses being tested. Study subjects should be randomly exposed without knowledge of the exposure condition (i.e., blinding of participants is ideal). Preference is given to balanced crossover (repeated measures) or parallel design studies which include control exposures (e.g., to clean filtered air). In crossover studies, a sufficient and specified time between exposure days should be provided to avoid carry over effects from prior exposure days. In parallel design studies, all arms should be matched for individual characteristics such as age, sex, race, anthropometric properties, and health status. In studies evaluating effects of disease, appropriately matched healthy controls are desired for interpretative purposes.

TOXICOLOGY:

1) Studies should clearly describe the primary and any secondary objectives of the study, or specific hypotheses being tested. 2) Studies should include appropriately matched control exposures (e.g., to clean filtered air, time matched). 3) Studies should use methods to limit differences in baseline characteristics of control and exposure groups. 4) Studies should randomize assignment to exposure groups and where possible conceal allocation to research personnel. 5) Groups should be subjected to identical experimental procedures and conditions; animal care including housing, husbandry, etc. should be identical between groups. 6) Blinding of research personnel to study group may not be possible due to animal welfare and experimental considerations; however, differences in the monitoring or handling of animals in all groups by research personnel should be minimized.

PROMPTING QUESTIONS:

Are there readily identifiable study weaknesses due to deficiencies in study design?

Crump, 2013, 3838553

Study evaluation