A Power Calculator for the Classical Twin Design
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Power is a ubiquitous, though often overlooked, component of any statistical analyses. Almost every funding agency and institutional review board requires that some sort of power analysis is conducted prior to data collection. While there are several excellent on line power calculators for independent observations, twin studies pose unique challenges that are not incorporated into these algorithms. The goal of the current manuscript is to outline a general method for calculating power in twin studies, and to provide functions to allow researchers to easily conduct power analyses for a range of common twin models. Several scenarios are discussed to demonstrate the importance of various factors that influence the power within the classical twin design and to serve as examples for the provided functions.
KeywordsPower Biometrical genetics Twin study Variance components
An earlier version of this paper was presented at the 2016 International Twin Workshop, March 10th, 2016. The author would like to thank the workshop faculty and students for their suggestions to improve the paper. This research was supported by by R25MH-019918 (PI: Hewitt), R01DA-018673 (PI: Neale) and R25DA-26119 (PI: Neale).
Compliance with ethical standards
Conflict of interest
Brad Verhulst declares that he has no conflicts of interest.
Human and animal rights and informed consent
This article does not contain any studies with human or animal participants performed by any of the authors.
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