Wansink 2006 ‐ study 1.
| Study characteristics | ||
| Methods | Setting: university campus, USA Design: quasi‐randomised controlled trial Recruitment: new students and their families visiting a display as part of a university open house were approached by a research assistant asking them to take part |
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| Participants | 269 adults aged over 18 participated. Although further demographic information were collected, no information is given about sample demographics | |
| Interventions | Intervention: glass container labelled 'new low fat M&M's' (sample size not reported) Control: glass container labelled 'new colours of regular M&M's' (sample size not reported) |
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| Outcomes | Energy (kcal) consumed; assessed by weighing the serving of M&M's that participants had served themselves (97.3% were observed to eat all that they had served themselves) | |
| Notes | Participants helped themselves freely to M&M's in labelled glass containers. The study was conducted over 2 days. The authors stated that "no industry or government agency funds supported this project" | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | High risk | Quasi‐randomisation based on the order in which people attended the open house |
| Allocation concealment (selection bias) | High risk | No allocation concealment |
| Blinding of participants and personnel (performance bias) All outcomes | High risk | It is unclear whether participants would have been aware of the other group as both groups seem to have been running at the same time. The M&M's were unusual colours (gold, teal, purple and white), which could have affected consumption behaviour. Research assistants administering the study are likely to have been aware of the different interventions and who was receiving each |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | Not reported, but outcome seems to have been objective (weighing M&M's), so lack of blinding may not have influenced the results |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Data seem to have been collected from all those who agreed to take part |
| Selective reporting (reporting bias) | Low risk | All relevant outcomes reported in the Methods section are reported in the Results section |
| Other bias | Low risk | No other potential threats to validity identified |