Hagger Curtin University, Perth, Australia University of Jyväskylä, Finland University of California, Merced, USA What Is a Behavioral Intervention?
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Why and How do Interventions Work? Evaluating Mechanisms of Impact Martin S. Hagger Curtin University, Perth, Australia University of Jyväskylä, Finland University of California, Merced, USA What is a Behavioral Intervention? Initiatives aimed at changing the behavior of a in a given population or group Targets a particular behavior or behavioral category Aim to solve or address a particular problem (e.g., prevention of illness or health risk) Some key features: – Target population – Content – Means of delivery – Means of evaluation – Deliverer/networks and contexts What is a Behavioral Intervention? Examples of behavioral interventions: – One-on-one, practitionerclient – Campaigns in existing networks/contexts School Workplace Social clubs Clinical – Education/persuasion (e.g., media/social media) – Legislation (e.g., seat belt use, smoking ban) – Regulation (e.g., fines for speeding) – Environmental/social planning (e.g., building design) – Fiscal measures (e.g., taxation on alcohol) How are Behavioral Interventions Typically Evaluated? Behavioral interventions typically evaluated in trials testing efficacy Also, effectiveness trials in ecologically-valid contexts Efficacy trials adopt designs like RCTs, pre-post designs to test effects against a comparator Efficacy/effectiveness evaluated using behavioral outcomes Relatively few evaluations try to ascertain mechanisms (Prestwich et al., 2015) Few elucidate the ‘black box’ on how they work Some Steps Toward Evaluating Intervention Mechanisms Identify target problem, behavior, population Identify (theoretical) determinants of behavior Identity methods/techniques to change determinants Put determinants and methods of change into a ‘logic model’ that outlines mechanisms Develop intervention content, delivery, and design of evaluation procedures Evaluate intervention using appropriate analyses for mechanism Basic Process (Logic) Model for Behavioral Interventions Behavior Modifiable Change Behavior Determinants Method Outcome Identify Determinants of Behavior Evidence for many behavioral interventions is often informed by psychological and behavioral theories Many theories, major focus on motivation/intention Ecological/environmental models, focus on context Considerable correlational research, less experimental research Modifiable Behavior Determinants Why is Theory Important? Answering the ‘what’ and ‘how’ questions Explanatory systems that summarize current knowledge on… – Personal/social/environmental factors (‘what’) – Mechanisms responsible (‘how’) – Targets for intervention Pose questions/hypotheses Permits confirmation, rejection Facilitates understanding, modification, replication and practice Examples of Theories Social cognitive theory (Bandura, 1963) Self-regulation theory (Kanfer, 1970) Health belief model (Becker, 1974) Protection motivation theory (Rogers, 1975) Theory of interpersonal behavior (Triandis, 1977) Theory of reasoned action (Fishbein & Ajzen, 1980) Self-determination theory (Deci, 1980) Transtheoretical model (Prochaska & DiClemente, 1982) Personality systems interaction theory (Kuhl, 1984) Theory of planned behavior (Ajzen, 1985) Theory of traying (Bagozzi, 1990) Health action process approach (Schwarzer, 1992) The I-change model (De Vries et al., 1998) Temporal self-regulation theory (Hall & Fong, 2007) CEOS theory (Borland, 2017) The ‘Major Theorists’ Theorist Theory Model Bandura Social cognitive theory Becker Health belief model Fishbein Reasoned action approach Deliberative Determinants Kanfer Self-regulation theory Personality/ Self-consistency Individual Triandis Theory of interpersonal Differences behavior Perceived Costs vs. Benefits Intention/ Behavior Social Influence Motivation Environmental Factors Self-Efficacy Anticipated Implicit Emotions Processes Habit Implicit Beliefs Past Behavioral Source: Conner & Norman (2015) Experience Cumulative Evidence of Behavioral Determinants Attitudes .30 to .40 .31 to .42 Intentions Behavior .12 to .31 Subjective Behaviors Norms Risk .26 to .35 Detection Physical activity Perceived Dietary Control Safe sex Abstinence Source: McEachen et al. (2011). Health Psychology Review. Identify Means to Change Determinants Determinants with established evidence with links to motivation/behavior Need to be linked with methods to change them Many methods/strategies/techniques available Relatively recently formal attempts to ‘map’ the methods Behavior Modifiable Change Determinants Methods Behavior Change Methods What is a behavior change method? ‘Active ingredients’ of behavior change interventions They ‘do the work’ in changing behavior They are irreducible and unique Could be seen as the ‘tools’ in a behavior change ‘toolbox’ Can be used independently or in conjunction with others Behavior Change Technique ‘Taxonomies’ Sources: Michie et al. (2013). Annals of Behavioral Medicine. Kok et al. (2016). Health Psychology Review. Behavior Change Technique ‘Taxonomies’ Structured organisation of unique methods that make up behavioral interventions “The need for a common vocabulary in terms of which content components of behavior change interventions can be defined and described” (Abraham & Michie, 2008, p. 380) Analogy: “Mapping the genome” of behavior change interventions ‘Mapping the Genome’ of Behavioral Interventions Intervention content Changing Changing Changing Changing Promote Promote Promote Enhance Change beliefs risk feelings norms positive self- goal social environ perceptions identity efficacy setting skills General Emphasise Others’ Promote Prompt Prompt Resisting information suscept. approval success mental goal social experience rehearsal setting pressure Use Describe Arouse Prompt Set graded Provide cues/ conseq. fear role goals feedback prompts Matching Identifying/classifying behavior change methods is an important first step But does not have utility if methods are not matched with key determinants/mediators from theory How do we identify methods that will reliably change determinants and, therefore, behavior? Numerous means to do this: – Knowledge of theory – Experimental evidence – Expert consensus Theory of Planned Behavior Interventions Intentions Attitude: d = .48 Norms: d = .49 Self-efficacy: d = .51 Intervention Attitude: d = .38 Norms: d = .36 Self-efficacy: d = .47 Health Behavior Source: Sheeran et al. (2016) Health Psychology, 35, 1178-1188 Theory of Planned Behavior Interventions Attitudes δ = .24 Norms δ = .14 Perceived Intervention δ = .26 Control δ = .34 Intentions δ = .50 Behavior Physical activity: δ = .54 Nutrition: δ = .20 Source: Steinmetz et al. (2016). How effective are behavior change interventions based on the Theory of Planned Behavior? Zeitschrift Fur Psychologie. Methods Used to Change Behavior in Theory-Based Interventions Behavior change method Frequency Information 47 Increasing skills 43 Persuasion 38 Planning 33 Social encouragement 20 Goal setting 19 Motivation 18 Self-monitoring 12 Source: Steinmetz et al. (2016). How effective are behavior change interventions based on the Theory of Planned Behavior? Zeitschrift Fur Psychologie. Expert Consensus Matching Methods with Determinants Methods to establish links between theory determinants and behavior change methods/techniques Expert consensus approach based on knowledge of the literature linking theory constructs to behavior change techniques e.g. Carey et al. (2019) examined 2,636 links between methods and constructs in behavioral intervention studies (k = 277) “Capacity beliefs” and “intention (motivation)” were most frequently cited Provides a searchable ‘matrix’ of methods and constructs Process and Mechanisms Links between methods and determinants is important, but does not outline processes Some methods are likely to be directly related to the determinant, which is likely to be directly related to behavior But others might act alongside (parallel) or together (synergistically) with other methods to affect change Theory and subsequent confirmatory research can assist in developing these links Developing the Intervention Methods identified are incorporated into intervention content to change behavior by changing the requisite determinants Need to decide… – Target population – Target context – Means of delivery – Protocol of delivery – Intervention intensiveness (‘dose’) – Evaluation processes (trial design, implementation, fidelity, outcome measures, mediator/determinants measures, duration) Evaluating Mechanisms Behavior Behavior Modifiable Change Determinants Method Outcome Post-intervention Coded variable measure of representing the determinant(s), intervention (e.g., 1 = preferably: received intervention; 0 = • Time lagged Post-intervention did not receive • Controlled for baseline measures of behavior intervention) • Validated and/or outcomes Example Autonomy .29 Perceived .20 Support Autonomy Attitude (Intervention) Support .29 .20 .40 .69 Autonomous Intention Physical Motivation Activity .23 Perceived Control Source: Chatzisarantis, N. L. D., & Hagger, M. S. (2009). Effects of an intervention based on self-determination theory on self-reported leisure-time physical activity participation. Psychology and Health, 24, 29-48. Summary of Steps for Evaluating Mechanisms Identify target problem, behavior, population Identify determinants of behavior Identity methods/techniques to change determinants Put determinants and constructs into a ‘logic model’ that outlines mechanisms Develop intervention content, delivery, and design of evaluation procedures