title: The role of answering behaviours on weight misreporting.
abstract: BACKGROUND
  Biases in self-reported weight are very common among young adults and adults. Although social norms are the most commonly accepted explanation for these misreports, corresponding evidence is scarce and conflict-ridden. An alternative explanation for biases in weight self-reports comes from answering behaviours; non-random rounding, formally an answering behaviour, has been found to play a significant role in several studies of weight misreporting. However, the presumably rich role of answering behaviours has seldom been explored. This study brings a second answering behaviour into the analysis: inconsistency.
  
  
  METHODS
  An inconsistency index was computed as an individual-level score from several questions across waves in the National Health and Nutrition Examination Survey. By regression analysis (N=3480 men and 1856 women) the simultaneous role of inconsistency and of non-random rounding on weight misreporting was explored.
  
  
  RESULTS
  Inconsistency was found to be associated with higher self-reported weights. Inconsistent individuals provided significantly different misreports, with women under-reporting 0.23[kg] (0.01-0.45) less and men over-reporting 0.42[kg] (0.02-0.82) more than their consistent counterparts. Inconsistency was found to play a simultaneous and substantially larger role than non-random rounding. This result was clearer among men than it was among women.
  
  
  CONCLUSIONS
  Although social norms are usually thought to be the central explanation of weight-biased misreports, there are other factors, such as answering behaviours, that might play a more influential role.
authors.affiliation: Instituto de Políticas Públicas, Universidad Diego Portales, Chile. Electronic address: ruben.castro@udp.cl.
authors.forename: Rubén
authors.initials: R
authors.lastname: Castro
mesh_terms: D000328:Adult; D001519:Behavior; D015982:Bias; D001828:Body Image; D001835:Body Weight; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009042:Motivation; D009749:Nutrition Surveys; D009765:Obesity / Q000523:psychology*; D057566:Self Report; D012737:Sex Factors
keywords: Answering behaviours; Social norms; Weight misreports