. Author manuscript; available in PMC: 2016 May 1.

Published in final edited form as: Obes Rev. 2015 Mar 5;16(5):362–375. doi: 10.1111/obr.12269

Table 1.

Substantive Findings and Study Design for Natural and Quasi-Experiments Evaluating Changes to Obesity, Weight, or Body Mass Index

Reference	Type of Intervention and Setting	Strength of Study Design	Study Design	Study Population and Size	Outcome, Timing and Method of Outcome Assessment	Direction (expected, unexpected, null)
Corvalan, 2008⁴⁵	Policy: School nutrition. Day care meal standards. (National, Chile)	+++	Within person longitudinal with comparison group¹	67,841 children aged 2–5 at 538 nursery schools	BMI z-scores, Obesity; 24 months post-intervention; Direct measurement	Mixed: Expected for phase 1 (reduction in BMI z-score and prevalence of obesity), null for phases 2 and 3 (no change)
Kaushal, 2007⁴⁴	Policy: Food voucher eligible participants. (National, U.S.)	++	Repeat cross-sectional with comparison group¹	72,173 low income immigrant adults	BMI; 24 months post-intervention; Self-report (survey)	Null (no association between food stamps and BMI)
MacDonald, 2010³⁷	Built Environment: Active Transport. Light rail (City in U.S.)	+++	Within person longitudinal with comparison group	498 adults	BMI, Obesity; 6 months post-intervention; Self-report (survey)	Expected (reduction in BMI and odds of obesity)

Indicates assignment to intervention and control groups was random or as-if random.