title: A Continuous Solution to the Norming Problem.
abstract: Conventional methods for producing test norms are often plagued with "jumps" or "gaps" (i.e., discontinuities) in norm tables and low confidence for assessing extreme scores. We propose a new approach for producing continuous test norms to address these problems that also has the added advantage of not requiring assumptions about the distribution of the raw data: Norm values are established from raw data by modeling the latter ones as a function of both percentile scores and an explanatory variable (e.g., age). The proposed method appears to minimize bias arising from sampling and measurement error, while handling marked deviations from normality-such as are commonplace in clinical samples. In addition to step-by-step instructions in how to apply this method, we demonstrate its advantages over conventional discrete norming procedures using norming data from two different psychometric tests, employing either age norms ( N = 3,555) or grade norms ( N = 1,400).
authors.affiliation: 1 Psychometrica, Institute for Psychological Diagnostics, Dettelbach, Bavaria, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Lenhard
authors.affiliation: 2 University of Wuerzburg, Bavaria, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lenhard
authors.affiliation: 3 University of Regensburg, Bavaria, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Suggate
authors.affiliation: 4 University of Basel, Suisse, Switzerland.
authors.forename: Robin
authors.initials: R
authors.lastname: Segerer
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D011594:Psychometrics / Q000379:methods*; D012016:Reference Values; D012044:Regression Analysis; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D009626:Terminology as Topic; D055815:Young Adult
keywords: continuous norming; curve fitting; data smoothing; norm generation; norm scores