The body silhouette images tool is a psychometric test, originally developed by Stunkard and colleagues in the 80’s for Caucasian body builds, although culturally relevant body image tools are also available. It illustrates a series of line drawings of men and women of distinct body sizes (from extreme thinness to extreme obesity). The scale has been successfully implemented to recall current and past body shape, including parental body shapes.
Although individuals have a tendency to perceive themselves as slimmer than they actually are and underestimate their weight status, there are strong correlations between measured BMI and figure ratings assigned by respondents and by unrelated observers, suggesting that this method can provide valid information about body shape and weight.
From a series of images (see Figure A.2.2 for example), individuals choose the body shape which best depicts either:
Figure A.2.2 Example of body silhouette rating scales used for females (top) and males (bottom) as used in the Fenland Study General Questionnaire. Participants choose the image which best depicts their body shape. This can be repeated for current and for previous body shape (e.g. at ages 10, 20, 30, 40). Participants can also choose the body image which most accurately reflects their parents’ body shape during middle age. Source: .
Selection of data source
The data can be collected by interview, can be self-administered, or be collected by an independent observer (e.g. friend or family member). They can be administered using pen and paper or an electronic device such as a mobile phone, tablet or computer, either face-to-face or remotely (e.g. by post or internet). Use of photographic or 3D images rather than illustrations is a recent option that may better represent different body types (e.g. individuals with wider hips or broader shoulders).
Obtaining cost-effective yet reliable measures of shape and weight is often difficult in large-scale surveys and epidemiological studies, especially in resource constrained settings (e.g. low income countries). The body shape tool can be used as an alternative in these scenarios. It is also an option for individuals who are reluctant or are too self-conscious to be measured objectively.
It is also used to study self-perceived body image and to rate attitudes regarding ideal body shape. The discordance with objective body weight and BMI may be informative.
An overview of subjective body shape methods is outlined in Table A.2.4.
Table A.2.4 Characteristics of subjective body shape methods.
|Number of participants
|Researcher burden of data collection
|Researcher burden of coding and data analysis
|Risk of reactivity bias
|Risk of recall bias
|Risk of social desirability bias
|Risk of observer bias
|Suitability for field use
|Participant literacy required
|Yes, if self-administered
Considerations relating to the use of subjective body shape methods in specific populations are described in Table A.2.5.
Table A.2.5 Use of subjective body shape methods in different populations.
|Infancy and lactation
|Toddlers and young children
|In general, men tend to misperceive their overweight status as normal more frequently than women.
|Older individuals mis-identify overweight status as normal more frequently than younger groups.
|Validity may vary by ethnic group.
|Individuals with lower socio-economic status are more likely to underestimate their weight status.
A method specific instrument library is being developed for this section. In the meantime, please refer to the overall instrument library page by clicking here to open in a new page.