Compare methods

	Vertical Scaling	Student Growth Percentiles
Field	Education	Education
Family	Latent structure	Regression model
Year of origin	2014	2009
Originator	Educational measurement tradition (Thurstone; Kolen & Brennan synthesis)	Damian W. Betebenner
Type	Construction of a single developmental score scale spanning multiple grades	Normative growth description via conditional quantile regression
Seminal source	Kolen, M. J., & Brennan, R. L. (2014). Test Equating, Scaling, and Linking: Methods and Practices (3rd ed.). Springer. ISBN: 9781493903160	Betebenner, D. W. (2009). Norm- and criterion-referenced student growth. Educational Measurement: Issues and Practice, 28(4), 42–51.
Aliases	Developmental Scaling, Vertical Linking, Cross-Grade Scaling, Growth Scale Construction	SGP, Conditional Status Percentiles, Betebenner Growth Percentiles, Quantile-Regression Growth Model
Related	4	4
Summary	Vertical scaling places tests written for different grade levels onto a single continuous score scale so that growth from one grade to the next can be measured in common units. Unlike horizontal equating, which links alternate forms intended to be interchangeable, vertical scaling deliberately links tests of differing difficulty and content to build a developmental continuum spanning, for example, grades 3 through 8. It is the measurement foundation that lets a fourth-grade and a fifth-grade score be subtracted to express how much a student grew.	Student growth percentiles (SGPs) describe how much a student grew academically relative to peers with similar score histories. Introduced by Damian Betebenner in 2009, the method fits a series of conditional quantile regressions of a current test score on prior scores, then reports each student's growth as the percentile rank they occupy within the distribution of students who had the same starting point. A student at the 70th growth percentile grew faster than 70 percent of academic peers, regardless of their absolute achievement level.