It’s not raining men: a mixed-methods study investigating methods of improving male recruitment to health behaviour research

Physical inactivity is a leading modifiable risk factor for chronic disease [1], yet approximately two-thirds of adults fail to meet recommended physical activity targets [2]. Gender is an important determinant of health-risk and health-promoting behaviours [3], with males being more likely to perform high-risk behaviours including smoking, unhealthy eating, excess alcohol consumption, and physical inactivity [4], and less likely to seek medical and psychological help [5] or participate in health-promotion programs [6]. Reviews further suggest that males comprise only about 20% of health behaviour research samples [7], contributing to a lack of evidence on how to increase men’s uptake of health-promoting behaviours [8].

The internet and online social networks (OSNs) are gaining interest as platforms for promoting engagement with health behaviour initiatives and research [9]. OSNs can provide an interactive and engaging medium to deliver health promotion content, which is positively associated with longer lasting intervention effects [10]. Research shows that use of OSNs is positively associated with sedentary behaviour [11], suggesting that such platforms may facilitate access to inactive populations, who are in greatest need of health behaviour interventions. Facebook is the largest of the OSNs, with 2.07 billion active users worldwide [12], 56% of which are men [13]. It therefore offers broad reach as a recruitment platform, whilst simultaneously allowing content to be targeted to specific users based on their demographic characteristics and geographical location.

Employing OSNs as recruitment platforms for health behaviour research is growing in popularity [14, 15]. Preliminary evidence generally supports OSNs as effective and cost-efficient platforms for targeting specific population subgroups [11, 16], but that the effectiveness of such campaigns is affected by advertisement characteristics such as message framing and image choice [17]. For example, Choi et al. [17] found that males’ level of engagement with Facebook advertising materials aiming to recruit participants to an online mental health study was greater when advertisements emphasised a ‘strength’ message (e.g. “how tough is your mind? Find out your psychological strength…”), when compared to a 'resilience' (e.g. “How resilient are you?”) or 'happiness' (e.g. “How happy are you?”) message. To maximise the potential of OSNs as research recruitment and health promotion platforms, there is a need for further evidence regarding the design of effective campaign content, particularly to reach males. The current study aims to contribute to this emerging body of research by addressing the following research questions:

This study took place within and alongside a large randomised controlled trial (RCT) evaluating a social and gamified physical activity intervention delivered via mobile phone application (app) called Active Team. Active Team users participate in clusters with between three and eight of their existing Facebook friends and use a pedometer to measure their daily step counts, which they then record in the app. Further detail regarding the Active Team RCT research methodology can be found elsewhere [18]. Ethical approval for the RCT and the current study (protocol number: P060–10) was granted by the University of South Australia’s Human Research Ethics Committee. Informed consent was obtained from all participants on page 1 of the online survey where participants indicated whether they had understood the participant information sheet and agreed to participate.

Active Team is currently undergoing evaluation in a RCT, which aimed to recruit 440 inactive adults with an approximately equal balance of male and females. Eligibility criteria required that all participants were aged between 18 and 65 years old, self-reported to be insufficiently active (< 150 min of moderate-vigorous physical activity per week), regular users of Facebook, and able to assemble or join a team with at least two other participants. To achieve the necessary cluster structure, ‘seed’ participants were recruited via Facebook in the first instance and encouraged to recruit at least two of their Facebook friends to form an eligible team. Initial/baseline recruitment campaigns resulted in more than 1600 formal expressions of interest (EOIs), however, the vast majority (> 80%) of these were from females, leading to a marked gender imbalance in our sample partway through recruitment.

This paper set out to share details of our efforts and experiences recruiting men to an online physical activity program using Facebook advertising. Our experience suggests that men are markedly less likely to respond to unisex ads compared with women. The response rate from men was improved substantially through use of targeted Facebook advertising incorporating evidence-based features, such as using images of men that appealed to leadership themes, and using concise text. Piloting of the potential advertisements was useful for identifying the images and text that were most appealing to our target audience. Despite our success in improving men’s engagement with study recruitment advertisement, the evidence-based campaign alone did not culminate in improved enrolments although we were able to boost male enrolments by asking female participants to invite males.

This study uncovered a number of principles relating to the design of effective health promotion advertisements targeting men via Facebook. Firstly, image selection may be more influential than text caption when it comes to stimulating audience engagement and click-throughs. One image that depicted a theme of male leadership and had a positive and friendly tone stood out as being particularly effective in attracting audience attention. This is consistent with previous research that found positively-framed appeals, particularly those that promote positive masculine norms (e.g. strength), to be most effective in engaging males with health programs [27]. Secondly, despite research that suggests sex appeal is effective in attracting males’ attention [22], our survey respondents reported that images featuring females were the least appealing and sent a confusing message. Consistent with the schema congruity hypothesis, this may reflect the human tendency to seek out information in our environment that is thematically consistent in order to minimise cognitive processing [28]. As previously suggested [29, 30], future campaigns should strive to present a clear, cohesive message that is consistent through both the text caption and the image. Finally, although Facebook does not limit the length of advertisement captions, target audience members showed a clear preference for briefer captions (< 35 words). This finding may reflect the message-dense nature of OSN content, often containing a myriad of information including advertisements, user-generated content, and promoted posts that make it difficult to grab the attention of users. It is therefore of utmost importance that health messages on OSNs are immediately understandable and brief enough (i.e., < 35 words) to be read and interpreted quickly.

Difficulties recruiting males to health behaviour research are not uncommon, with physical activity interventions that target both males and females reporting much higher rates (> 80%) of female participation [7]. In the current study we observed that many of the males who did click through to our landing page and complete some or all of the baseline assessments did not go on to complete their formal enrolment in the study. This phenomenon may be a result of the more intensive nature of the physical activity intervention that also had a relatively long timeframe of commitment (9 months). Participants are required to complete assessments over a nine-month period, and being a three-arm RCT, participants’ chance of random allocation to the treatment arm is just 33%. Previous studies have similarly suggested that Facebook advertising may be better suited to recruiting participants to less intensive or once-off data collection rather than ongoing participation in intervention studies [31, 32].

There was also some anecdotal evidence to suggest that the social networking nature of Active Team was more appealing to women than it was to men. The requirement to form a team of three to eight existing Facebook friends appeared to be a significant barrier to the enrolment of males, but not females, into the study. A similar experience was reported in the ManUp RCT, which sought to improve physical activity and dietary practices in middle-aged men using a Web-based approach that included an intentionally designed social network [33]. Of the 214 participants that were randomised to the OSN component, only 21 participants elected to find a ‘mate’ and no participants had more than one mate in this network. It is possible that males are more inclined to participate in individual-based physical activity programs rather than social ones, or perhaps they would prefer to interact with strangers rather than people they know. Lifestyle, use of time patterns, and physical activity preferences are also likely determinants of male participation in health behaviour research. Although the bulk of physical activity interventions are based on a target of 10,000 steps per day, research suggests that males may prefer a more diverse range of activities including walking, swimming, cycling, and team sports [34]. In addition, males are more likely to partake in full time employment than women [35], and this may limit opportunities to accumulate step counts throughout the day via incidental activity. For these reasons, interventions that promote time-based goals, such as 30 min of activity per day rather than 10,000 steps per day, may be more appealing to men [34].

There are a number of limitations that are worth considering when interpreting these findings. Firstly, our Facebook advertisements were displayed to different audiences during each of the different phases (i.e., results reflect an open cohort design). Although this characteristic of the study design was necessary as a means to test the advertisements in real-life conditions, it is important to acknowledge that conclusions are correlational rather than causal. Secondly, online survey respondents were recruited via the authors’ personal Facebook pages and local Facebook interest groups, which may have created some biases in our sample towards users who are highly engaged with their community and health. Finally, the target population in this study was broad and included adults aged 18–65, which may have shrouded any effects of age on responses to health information. Further research is needed to explore how age, and other individual differences including socio-economic status and personality affect responses to health information even within the male sub-group.

Whilst not a direct limitation of the current study, there are challenges associated with the use of Facebook advertising that should be briefly mentioned here. There is little information available about the algorithm Facebook uses to determine the amount of exposure that an ad receives. The algorithm controls the numbers of ads that a user sees, and the content of the ads based on a combination of factors including the parameters set by the advertiser, previous engagement with the ad (likes, comments, and shares).

Under-recruitment of males is a general limitation of health behaviour research. Since the typical research participant in health behaviour research is a university-education, middle-aged woman, conclusions about men may be underpowered or difficult to generalise. In light of evidence that males are less likely to seek help for health-related issues [36] and less likely to participate in health promoting programs [3], expanding our understanding of how to effectively promote health programs to men is an essential avenue for future research. The current study provides some valuable insights into how recruitment rates for male participants to physical activity programs can be improved. Despite careful development and implementation, an evidence-based Facebook advertisement campaign was not enough to address the gender imbalance within the RCT sample, however, the approach of encouraging female participants to invite male participants was much more successful, and resulted in a 66% relative increase in male enrolment.