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Reference percentiles for pubertal stage variables by age, based on the Dutch 1997 growth study (Fredriks et al., 2000). Used by calculate_sds to convert an observed age/stage combination into a standard deviation score.

Usage

nl1997

Format

A list with six components, one per pubertal stage variable: gen, phb, tv, bre, phg and men. Each component is a data frame whose first column is age and whose remaining columns hold the age at which 50 the reference population reaches each stage.

Source

Fredriks AM, van Buuren S, Burgmeijer RJ, et al. (2000). Continuing positive secular growth change in The Netherlands 1955-1997. Pediatric Research, 47(3), 316-323. Percentiles were refit in R from data-raw/data/pub.ref.1997r.txt, correcting testis-volume (tv) fitting errors present in the original S-Plus-fitted pub.ref.1997.txt; the genital-stage columns match Table 5 of van Buuren S (2014). Growth charts of human development. Statistical Methods in Medical Research, 23(4), 346-368. doi:10.1177/0962280212473300