This work sought to investigate the relation between social desirability and self-reported health risk behaviors (e.g., alcohol use, drug use, and smoking) in web-based research. Self-report measures are a common way of gathering data in research on health risk behaviors. In several commonly used planning models of health promotion [1
], self-reports are used in several phases, for example, in the problem analysis (e.g., behavioral diagnosis) and in the evaluation of interventions (e.g., effectiveness). In tailored interventions, self-reports are used to tailor the intervention to respondents' behavior and determinants of this behavior [3
]. One reason of why self-reports are used in research on health risk behaviors is that they require fewer resources (e.g., financial, logistical) and have higher specificity (e.g., quantity/frequency measures) compared to bio-medical measures such as hair testing and urine screening for drug use or an air carbon monoxide monitor for smoking. Another reason of why self-reports are used in research is that interventions are nowadays increasingly delivered through the Internet [5
]. Internet-delivered interventions often rely on self-reports, because bio-medical measures are not consonant with grounds to deliver interventions through the Internet such as accessibility (24/7 worldwide), convenience (e.g., participating in the comfort of one's own home), and anonymity (e.g., no human contact).
A study by Kreuter, Presser, and Tourangeau [7
] indicated an increase in the reporting of sensitive information in web-based questionnaires relative to conventional telephone interviewing, whereas another study found no differences when comparing web-based with paper-and-pencil questionnaires [8
]. On the one hand, some researchers stated that the social distance [9
] and the impersonal nature of the Internet might inhibit trust development [10
]. Link and Mokdad [11
], for example, found the use of web-based research with the general public to be problematic (e.g., because of obtaining considerable variation in the estimates for heavy drinking). On the other hand, previous research indicated that smoking behavior can indeed be reliably assessed by self-reports obtained via the web [12
]. Furthermore, McCabe and colleagues [14
] provide strong evidence that web-based research can be used as an effective mode for collecting alcohol and other drug use data.
While some studies speak in favor of assessing alcohol use and addiction severity via the web [15
], others found underreporting of undesirable behaviors, such as drug use and alcohol use [17
]. Social desirability may provide an explanation for these different findings. Social desirability is the tendency of respondents to distort self-reports in a favorable direction, for example, by providing responses that - to their belief - are consistent with social norms and expectations [18
There has been a long discussion in the literature whether social desirability is a personality trait or a situational strategy [19
]. Previous research using latent state-trait models indicates that the largest proportion of variance in responses is attributable to differences in the trait. A small but significant proportion of variance is due to situation-specific conditions [20
]. A condition that tends to enhance the possibility of social desirability bias is a highly sensitive topic [21
]. Moreover, significant relationships between social desirability and self-reports of risk-taking behavior have been revealed previously [22
]. Hence, it is reasonable to assume that many areas of public health, particularly self-reports of health risk behaviors, are prone to social desirability bias. If self-reported measures are indeed influenced by social desirability, controlling for social desirability may remove some of the error due to the use of self-report measures and therewith improve the validity of these measures [23
Previous research found minimal evidence of an influence of social desirability on scores from two self-report measures of measuring physical activity in young adults [24
] and no evidence for a social desirability bias with a self-report condom use scale [25
]. Nevertheless, these studies were not web-based, thereby ignoring the social distance and impersonal nature of the Internet. Mode comparison studies (i.e., in which web-based assessment is compared with, for example, paper-and-pencil assessment [26
] or with telephone interviewing [28
]) generally have relied on one of three different designs: randomization after recruitment (true experimental design), randomization before recruitment (where there may be differences in response between modes), and a test-retest design (where respondents need to answer questions in two or more modes consecutively). A recent report on online panels by the American Association for Public Opinion Research [29
] concluded that, regardless of design, there were higher reports of socially undesirable attitudes and behaviors in self-reported web-based questionnaires than in face-to-face interviews. For example, web-based questionnaires yielded higher reports of smoking [30
] and alcohol use [31
]. These studies compared different modes regarding self-reports of health risk behaviors (e.g., differences in prevalence rates) and attributed the studies' results to characteristics of that mode. In other words, these studies assumed that certain modes lead to more or less socially desirable responding. Hence, the focus of these studies was not on the influence of social desirability itself. It is possible, for example, that there were other factors, besides social desirability, that led to differences in reports of health risk behaviors. In contrast to the work at hand, these studies did not investigate whether differences in social desirability resulted in differences in self-reports of health risk behaviors.
If social desirability is found out to be an issue in web-based research, this would raise concerns about the validity of web-based research on health risk behaviors. Therefore, in the work at hand we were specifically interested in the relationship between social desirability and the self-reporting of health risk behaviors in web-based research. We investigated the association between social desirability measures and self-reported health risk behaviors. Hence, the following research question was put forward:
To what extent is social desirability associated with self-reported health risk behaviors in web-based research?
Because of the social distance [9
] and the impersonal nature of the Internet [10
], we did not expect social desirability to have a biasing influence in web-based research on health risk behaviors. Additionally, we investigated potential moderating effects of socio-demographics on the effects of social desirability on self-reports of health risk behaviors. In line with a meta-analysis about social desirability distortion [32
], we did not expect any moderating effects of socio-demographics.
Due to the explorative nature of our research, we collected data in three longitudinal studies among randomly selected members of two online panels using several social desirability measures. In the first study, the traditional social desirability measure was used: the Marlowe-Crowne Scale [33
]. For this measure, items were selected from personality questionnaires that described behaviors that were highly desirable but unlikely to be true or undesirable but likely to be true. High scorers on the Marlowe-Crowne Scale are more amendable to social influence compared to low scorers. Therefore, higher scores are probably related to impression management; a tendency to intentionally distort one's self-image to be perceived favorably by others [34
Gawronski and colleagues [35
] argued, however, that the Marlowe-Crowne Scale may be too general to capture motivational distortions in self-reports and a more differentiated social desirability measure distinguishing between self-deception and impression management may be needed. Self-deception is an unintentional propensity to portray oneself in a favorable light, manifested in positive but honestly believed self-descriptions [34
]. Impression management, by contrast, is people's tendency to intentionally distort their self-presentation to be perceived favorably by others The Balanced Inventory of Desirable Responding (BIDR) [36
] appeared to be useful for our purposes, since this measure has two subscales measuring both self-deception (BIDR-SE) and impression management (BIDR-IM). The BIDR-IM was used in the second study because this subscale is more closely related to the Marlowe-Crowne Scale and is deemed to be instrumental for our purposes.
Another critique on the Marlowe-Crowne Scale says this scale reflects the social standards of the late 1950 s (e.g., "I am always courteous, even to people who are disagreeable.") and is less appropriate to be used nowadays [37
]. To remedy this limitation, the Social-Desirability Scale-17 (SDS-17) was developed [37
]. This is a new scale in the Marlowe-Crowne style, but with up-to-date contents. To avoid falling prey to potential problems of validity with the Marlowe-Crowne Scale, in the third study, we used the SDS-17 next to both subscales of the BIDR. We hypothesized - in line with Stöber [37
] - that the SDS-17 is more highly correlated with the BIDR-IM than with the BIDR-SE. Besides differences in correlations among scales, we did not hypothesize differences among the scales regarding their relationship to self-reports of health risk behaviors, since we did not expect social desirability to have an influence in web-based research on health risk behaviors in the first place.