title: Q-learning: a data analysis method for constructing adaptive interventions.
abstract: Increasing interest in individualizing and adapting intervention services over time has led to the development of adaptive interventions. Adaptive interventions operationalize the individualization of a sequence of intervention options over time via the use of decision rules that input participant information and output intervention recommendations. We introduce Q-learning, which is a generalization of regression analysis to settings in which a sequence of decisions regarding intervention options or services is made. The use of Q is to indicate that this method is used to assess the relative quality of the intervention options. In particular, we use Q-learning with linear regression to estimate the optimal (i.e., most effective) sequence of decision rules. We illustrate how Q-learning can be used with data from sequential multiple assignment randomized trials (SMARTs; Murphy, 2005) to inform the construction of a more deeply tailored sequence of decision rules than those embedded in the SMART design. We also discuss the advantages of Q-learning compared to other data analysis approaches. Finally, we use the Adaptive Interventions for Children With ADHD SMART study (Center for Children and Families, University at Buffalo, State University of New York, William E. Pelham as principal investigator) for illustration.
authors.affiliation: Institute for Social Research, University of Michigan, Ann Arbor, MI 48106, USA. inbal@umich.edu
authors.forename: Inbal
authors.initials: I
authors.lastname: Nahum-Shani
authors.forename: Min
authors.initials: M
authors.lastname: Qian
authors.forename: Daniel
authors.initials: D
authors.lastname: Almirall
authors.forename: William E
authors.initials: WE
authors.lastname: Pelham
authors.forename: Beth
authors.initials: B
authors.lastname: Gnagy
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Fabiano
authors.forename: James G
authors.initials: JG
authors.lastname: Waxmonsky
authors.forename: Jihnhee
authors.initials: J
authors.lastname: Yu
authors.forename: Susan A
authors.initials: SA
authors.lastname: Murphy
mesh_terms: D003627:Data Interpretation, Statistical; D003661:Decision Support Techniques; D006801:Humans; D016014:Linear Models; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D012044:Regression Analysis