['The current study compared two interventions for promotion of stair climbing in the workplace, an information-based intervention at a health information day and an environmental intervention (point-of-choice prompts), for their effectiveness in changing stair climbing and cost per employee.', 'Interrupted time-series design.', 'Four buildings on a university campus.', 'Employees at a university in the United Kingdom.', 'Two stair-climbing interventions were compared: (1) a stand providing information on stair climbing at a health information day and (2) point-of-choice prompts (posters).', "Observers recorded employees' gender and method of ascent (n = 4279). The cost of the two interventions was calculated.", 'Logistic regression.', 'There was no significant difference between baseline (47.9% stair climbing) and the Workplace Wellbeing Day (48.8% stair climbing), whereas the prompts increased stair climbing (52.6% stair climbing). The health information day and point-of-choice prompts cost $773.96 and $31.38, respectively.'] Is effectiveness and cost of two stair-climbing interventions-less more?