Hawthorne Effect in Screening Ambulatory Activity Status Using Wearable Pedometers Varies Across Age Groups

Using wearable step-counting devices is a common method in scientific research to evaluate ambulatory activity. The Hawthorne effect, defined as an increase in productivity or performance resulting from the perception of being monitored, is often overlooked by researchers and remains poorly understood, particularly in the assessment of ambulatory activity using wearable step-counting devices. This study aimed to assess ambulatory activity levels in various age groups and quantify the impact of wearing step-counting devices on the daily ambulatory activity in men.

A convenience sample of 60 men was included and allocated into 3 age groups (20-25, 40-45, and 60-65 years), with 10 participants in the control group and 10 in the experimental group for each age category. Step count data were collected in 2 stages: first, from the previous week, month, and 6 months; second, after 7 days of wearing a digital sham pedometer watch. Participants in the experimental groups were told that the watch is a step-counting device and that their activity was being monitored, even though all data were collected from the iPhone "Health" application (iOS 16.5), while the control group remained blinded until the last data collection was completed.

Comparison of pre- and postintervention data showed positive Hawthorne effect on the level of ambulatory activity in young, middle-aged, and older adults by 62.90%, 55.58%, and 81.96%, respectively. Significant differences were found between each experimental group and its respective control group after the 1-week intervention (p<0.001).

The research concludes that all experimental groups increased their step count by more than 50% compared with baseline levels.