title: Reliability of a field based 2D:4D measurement technique in children.
abstract: BACKGROUND
  There is limited literature on the relationship between second to fourth finger digit ratio (2D:4D) and health- and skill-related fitness in children. To examine this relationship it is important to establish a reliable method of assessing 2D:4D for use with large groups of children.
  
  
  OBJECTIVE
  The aim of the study was to examine the reliability of a field-based 2D:4D measure in children. METHODS/RESEARCH DESIGN: Fifty 8-11 year olds had 2D:4D of the right hand measured using a Perspex table top, a digital camera, and Adobe Photoshop software. Second to fourth finger digit ratio (and 2D and 4D) intra-observer and inter-observer reliabilities were assessed on the same day and intraobserver reliability was measured between days. Limits of agreement (LoA), coefficient of variation (CV) and Pearson's correlation coefficient were used for statistical analysis.
  
  
  RESULTS
  High correlation coefficients (r=0.95-0.99) and low CV's (0.4-1.2%) were reported for intra- and inter-observer reliabilities on the same day and between days. LoA revealed negligible systematic bias with random error ranging from 0.02 to 0.12.
  
  
  CONCLUSIONS
  These findings suggest that 2D:4D (and 2D and 4D) assessment in children using digital photography provides a reliable measure of 2D:4D that can be used during field-based testing.
authors.affiliation: Sports and Exercise Sciences, Glyndwr University, Wrexham LL11 2AW, UK.
authors.forename: R M
authors.initials: RM
authors.lastname: Ranson
authors.forename: S R
authors.initials: SR
authors.lastname: Taylor
authors.forename: G
authors.initials: G
authors.lastname: Stratton
mesh_terms: D002648:Child; D061827:Dimensional Measurement Accuracy; D005260:Female; D005385:Fingers / Q000033:anatomy & histology* / Q000254:growth & development; D006801:Humans; D008297:Male; D015588:Observer Variation; D010781:Photography