Health Action Process Approach

Theories  of  health  behavior  change  are  needed to   explain,   predict,   and   improve   self-regulation  of  physical  activity.  Such  theories  are  being divided  into  continuum  models  and  stage  models.  In  continuum  models,  people  are  positioned along a range that reflects the likelihood of action. Influential  predictor  variables  are  identified  and combined  within  one  prediction  equation.  The goal of an intervention is to move the person along this route toward action. Health promotion, then, focuses on increasing all model-inherent variables in all persons, without matching treatments to particular audiences. The theory of planned behavior (TPB), developed by Icek Ajzen, is one such continuum model.

In contrast, according to stage models, health behavior change consists of an ordered set of categories (or stages) into which people are classified. These  categories  reflect  cognitive  or  behavioral characteristics,  such  as  the  intention  to  perform a  behavior.  The  main  purpose  of  applying  stage models lies in the identification of relatively homogeneous  target  groups  for  interventions  and  the design  of  stage-matched  treatments.  The  most popular  stage  theory  of  health  behavior  change is  the  transtheoretical  model  (TTM),  developed by  James  Prochaska,  that  proposes  five  stages  of change.

Both continuum models and stage models have their  advantages  and  disadvantages.  Continuum models  have  been  found  useful  for  explanation and  prediction,  whereas  stage  models  are  often preferred  to  guide  interventions.  For  health  promotion, the continuum models are often too general because all variables involved in such a model need  to  be  addressed  in  interventions,  without considering  the  special  needs  of  particular  subgroups  of  participants.  However,  it  is  possible  to integrate both approaches when researchers use a continuum  model  as  a  theoretical  template  and, when it comes to interventions, subdivide the audience into stage groups to allow for stage-matched treatments.  The  health  action  process  approach (HAPA),  developed  by  Ralf  Schwarzer,  is  such  a hybrid model with a continuum layer as well as a stage layer.

Mediating Mechanisms

The traditional continuum models have been criticized  mainly  because  of  the  so-called  intention– behavior  gap  (referring  to  the  frequent  failure  of intention  to  predict  behavior).  HAPA  explicitly includes  postintentional  factors  to  overcome  this gap. It suggests a distinction between (1) preintentional  motivation  processes  that  lead  to  a  behavioral  intention,  and  (2)  postintentional  volition processes  that  lead  to  the  actual  health  behavior. Within the two phases, different patterns of social cognitive predictors may emerge (see Figure 1). In the initial motivation phase, a person develops an intention  to  act.  In  this  phase,  risk  perception  is seen as a distal antecedent (e.g., “I am at risk for cardiovascular  disease”).  Risk  perception  in  itself is insufficient to enable a person to form an intention. Rather, it may set the stage for a contemplation  process  and  further  elaboration  of  thoughts about  consequences  and  competencies.  Similarly, positive outcome expectancies  (e.g., “If I exercise five times per week, I will reduce my cardiovascular risk”) are chiefly seen as being important in the motivation phase, when a person balances the pros and cons of certain behavioral outcomes. Further, one needs to believe in one’s capability to perform a  desired  action,  perceived  self-efficacy  (e.g.,  “I am capable of adhering to my exercise schedule in spite  of  the  temptation  to  watch  TV”).  Perceived self-efficacy operates in concert with positive outcome  expectancies,  both  of  which  contribute  to forming  an  intention.  Both  beliefs  are  needed  for forming  intentions  to  adopt  difficult  behaviors such as regular physical exercise.

After forming an intention, the volitional phase is  entered.  When  a  person  is  inclined  to  adopt  a particular health behavior, the good intention has to  be  transformed  into  detailed  instructions  on how to perform the desired action. Once an action has  been  initiated,  it  has  to  be  maintained.  This is  not  achieved  through  a  single  act  of  will  but involves self-regulatory skills and strategies. Thus, the  postintentional  phase  is  further  broken  down definition  that  includes  irreversibility  and  invariance. The terms phase or mindset may be equally suitable for this distinction. The basic idea is that individuals pass through different phases on their way to behavior change. Thus, interventions may be most efficient when tailored to these particular mindsets.

For example, preintenders are supposed to benefit  from  confrontation  with  outcome  expectancies  and  some  level  of  risk  communication.  They need  to  learn  that  the  new  behavior  like  becoming  physically  active  has  positive  outcomes,  such as well-being, weight loss, and fun, as opposed to into  more  proximal  factors,  such  as  planning, coping  self-efficacy,  and  recovery  self-efficacy. Additional  volitional  constructs  that  have  been included in HAPA research are action control and social support.


Figure 1    Health Action Process Approach

Including  planning  and  self-efficacy  as  volitional mediators renders the HAPA into an implicit stage model because it implies the existence of at least  a  motivational  and  a  volitional  phase.  The purpose  of  such  a  model  is  twofold:  It  allows  a better  prediction  of  behavior,  and  it  reflects  the assumed  causal  mechanism  of  behavior  change. Research that is based on this continuum layer of the model employs path-analytic methods.

Preintenders, Intenders, Actors

When  it  comes  to  the  design  of  interventions, one can consider turning the implicit stage model into  an  explicit  one.  This  is  done  by  identifying individuals  who  are  located  either  in  the  motivational stage or in the volitional stage. Then, each group receives a specific treatment that is tailored to this group. Moreover, it is useful and theoretically meaningful to subdivide the volitional group further into persons who perform and those who only  intend  to  perform.  In  the  postintentional– preactional stage, individuals are labeled intenders, and in the actional stage actors. Thus, a pragmatic subdivision within the health behavior change process  yields  three  groups:  preintenders,  intenders, and actors.

The  term  stage  in  this  context  was  chosen  to allude  to  the  stage  theories,  but  not  in  the  strict the negative outcomes that accompany the current (sedentary) behavior, such as developing an illness or being overweight. They also need to develop an optimistic belief that they are capable of performing the critical behavior.

In contrast, intenders should not benefit much from  health  messages  in  the  form  of  outcome expectancies  because,  after  setting  a  goal,  they have already moved beyond this mindset. Rather, they  should  benefit  from  planning  to  translate their intentions into action.

Finally, actors should be prepared for particular high-risk situations in which lapses are imminent. Interventions  help  them  if  they  desire  to  change their  routines  by  adopting  or  altering  a  behavior, for example.

Five Principles

The  HAPA  is  designed  as  an  open  architecture that  is  based  on  principles  rather  than  on  specific  testable  assumptions.  Developed  in  1988,  it was  an  attempt  to  integrate  the  model  of  action phases by Heinz Heckhausen and Peter Gollwitzer, with  social  cognitive  theory  developed  by  Albert Bandura, based on five principles.

Principle 1: Motivation and volition.  The health behavior   change   process   is   divided   into   two phases. There is a switch of mindsets when people move from deliberation to action. First comes the motivation  phase  in  which  people  develop  their intentions.   Afterwards,   they   enter   the   volition phase.

Principle 2: Two volitional phases.  In the volition phase, there are two groups of people: those who did  not  yet  translate  their  intentions  into  action, and those who did. Thus, there are inactive as well as active persons in this phase. In other words, in the volitional phase one finds intenders as well as actors who are characterized by different psychological   states.   In   addition   to   health   behavior change as a continuous process, one can also create three categories of people with different mindsets, depending on their current location within the course of behavior change: preintenders, intenders, and actors.

Principle  3:  Postintentional  planning.  Intenders who  are  in  the  volitional  preactional  stage  are motivated to change, but they do not act because they  might  lack  the  right  skills  to  translate  their intention into action. Planning is a key strategy at this   point.   It   serves   as   an   operative   mediator between intentions and behavior.

Principle 4: Two kinds of mental simulation.  Planning can be divided into action planning and coping   planning.   Action   planning   pertains   to   the when, where, and how of intended action. Coping planning includes the anticipation of barriers and the design of alternative actions that help to attain one’s goal in spite of impediments.

Principle 5: Phase-specific self-efficacy.  Perceived self-efficacy is required throughout the entire process.  However,  the  nature  of  self-efficacy  differs from phase to phase. This is because there are different   challenges   as   people   progress   from   one phase to the next one. Goal setting, planning, initiative, action, and maintenance all pose challenges that  are  not  of  the  same  nature.  Therefore,  we distinguish    between    preactional    self-efficacy, coping   self-efficacy,   and   recovery   self-efficacy. Sometimes  the  terms  task  self-efficacy  instead  of preaction   self-efficacy,   and   maintenance   self efficacy   instead   of   coping   and   recovery   self efficacy are preferred.

Assessment of Constructs

Risk Perception.  Risk perception can be measured by items such as “How high do you rate the likelihood  that  you  will  ever  get  one  of  the  following diseases:   (a)   cardiovascular   disease   (e.g.,   heart attack, stroke), (b) diseases of the musculoskeletal system   (e.g.,   osteoarthritis,   herniated   vertebral disk)?” Any other health risk can be added, if relevant to the research context.

Outcome  Expectancies.  Positive  outcome  expectancies  (pros)  and  negative  outcome  expectancies (cons) can be assessed, for example, with the stem “If I engage in physical activity at least three times per  week  for  20  minutes  .  .  .”  followed  by  pros such  as  “then  I  feel  better  afterwards,”  or  “then I meet friendly people,” and followed by cons such as “then every time would cost me a lot of money,” or “then I would be financially depleted.”

Self-efficacy.  Perceived   motivational   and   volitional self-efficacy can be composed of items such as  the  following.  Motivational  self-efficacy  (task self-efficacy)  refers  to  the  goal-setting  phase  and can be measured with the stem “I am certain . . .” followed  by  items  like  “that  I  can  be  physically active on a regular basis, even if I have to mobilize myself,”  or  “that  I  can  be  physically  active  on  a regular basis, even if it is difficult.” Volitional self efficacy refers to the goal-pursuit phase. It can be subdivided  into  coping  self-efficacy  and  recovery self-efficacy.  Coping  self-efficacy  has  been  measured  with  the  stem  “I  am  capable  of  strenuous physical exercise on a regular basis . . .” followed by barriers like “even if it takes some time until it becomes   routine,”   or   “even   if   I   need   several attempts until I will be successful.” Items on recovery  self-efficacy  can  be  worded  “I  am  confident that I can resume a physically active lifestyle, even if I have relapsed several times,” “I am confident that I am able to resume my regular exercises after failures  to  pull  myself  together,”  or  “I  am  confident  that  I  can  resume  my  physical  activity,  even when feeling weak after an illness.”

Intention.  Intention   to   perform   a   behavior   is assessed  in  correspondence  to  the  behavior  itself: for  example,  “I  intend  to  perform  the  following activities at least 3 days per week for 20 minutes: strenuous  (heart  beats  rapidly,  sweating)  physical activities,”  “moderate  (not  exhausting,  light  perspiration) physical activities,” and “mild (minimal effort, no perspiration) physical activity.” Answers can range, for example, from not at all true (1) to absolutely true (6). Alternatively, intention can be assessed  in  terms  of  frequency  and  duration  of more   specific   behaviors:   (a)   physiotherapeutic exercises (e.g., back training), (b) fitness activities (e.g., using an exercise bike), (c) resistance training (training muscle strength, e.g., on machines), and (d) physical activity while commuting (e.g., going by bicycle or walking for longer distances).

Planning.  Action  Planning  can  be  assessed  with items addressing the when, where, and how of the activity: for example, “I have already planned . . .” (1)  “which  physical  activity  I  will  perform  (e.g., walking),”  (2)  “where  I  will  be  physically  active (e.g., in the park),” (3) “on which days of the week I will be physically active,” and (4) “for how long I  will  be  physically  active.”  Coping  planning,  on the  other  hand,  can  be  measured  with  the  item stem “I have made a detailed plan regarding . . .” and the items (1) “what to do if something interferes  with  my  plans,”  (2)  “how  to  cope  with possible  setbacks,”  (3)  “what  to  do  in  difficult situations  in  order  to  act  according  to  my  intentions,” (4) “which good opportunities for action to take,” and (5) “when I have to pay extra attention to  prevent  lapses.”  Another  option  is  to  ask  participants  to  actually  generate  their  plans,  which, however, confounds measurement and treatment.

Action  Control.  While  planning  is  a  prospective strategy, that is, behavioral plans are made before the  situation  is  encountered,  action  control  is  a concurrent   self-regulatory   strategy,   where   the ongoing  behavior  is  continuously  evaluated  with regard  to  a  behavioral  standard.  Action  control can  be  assessed  with  a  six-item  scale  comprising three  facets  of  the  action  control  process:  selfmonitoring   (“I   consistently   monitored   myself whether I exercised frequently enough,” or “I consistently monitored myself when, where, and how long I exercise”), awareness of standards (“I have always been aware of my prescribed training program,”  or  “I  often  had  my  exercise  intention  on my  mind”),  and  self-regulatory  effort  (“I  really tried hard to exercise regularly,” or “I took care to practice as much as I intended to”).

Staging.  When using the continuum model for the prediction  of  behavior,  these  variables  are  being specified  as  predictors  and  mediators  in  a  path model  (see  Figure  1).  When  employing  the  stage variant to conduct an intervention study, an assessment of stages is necessary. Stage theories employ algorithms for the staging procedure which can be regarded as a fast and frugal tree with satisfactory validity.  For  a  three-stage  procedure,  one  needs two steps. First, behavior is assessed on the basis of a context-specific dichotomous criterion (yes = already  active,  no  =  not  yet  sufficiently  active). Those   who   meet   the   preselected   criterion   are defined as actors. Those who don’t are subject to the  second  step  by  asking  them  whether  they intend to become active or not. If they do intend, they are defined as intenders; if they don’t, they are nonintenders  (or  preintenders).  Such  straightforward diagnostic procedures may be too simple to account  for  response  bias  and  temporal  fluctuation. However, when subdividing large samples to assign stage-matched treatments, such a pragmatic procedure results in more homogeneous subgroups that allow for more effective interventions.


In  sum,  the  HAPA  has  two  layers:  a  continuum layer  and  a  phase  (or  stage)  layer.  Depending on  the  research  question,  one  might  choose  one or  the  other.  HAPA  is  designed  as  a  sequence  of two  continuous  self-regulatory  processes,  a  goalsetting  phase  (motivation)  and  a  goal-pursuit phase  (volition).  The  second  phase  is  subdivided into  a  preaction  phase  and  an  action  phase.  One can superimpose these three phases on the continuum model as a second layer and regard phase as a moderator.

This  two-layer  architecture  allows  switching between the continuum model and the stage model, depending  on  the  given  research  question.  The stage  layer  is  useful  for  designing  stage-matched interventions. For preintenders, one needs risk and resource communication, for example by addressing  the  pros  and  cons  of  a  critical  behavior.  For intenders, planning treatments are helpful to support those who lack the necessary skills to translate their intentions into behavior. And for actors, one  needs  to  stabilize  their  newly  adopted  health behaviors by relapse prevention strategies.

The  HAPA  allows  both  the  researcher  and the  practitioner  to  make  a  number  of  choices. Although it was initially inspired by distinguishing between a motivational and a volitional stage, and later  expanded  to  the  distinction  between  preintenders, intenders, and actors, one need not necessarily group individuals according to such stages. If  the  purpose  is  to  predict  behavior  change,  one would  specify  a  mediator  model  that  includes postintentional  constructs  (such  as  planning  and volitional  self-efficacy)  as  proximal  predictors  of performance.

For  stage-tailored  interventions,  however,  usually three stage groups would be established. This does not exclude the possibility of generating more than three stages. For example, for some research questions,  one  might  subdivide  the  preintenders into precontemplators and contemplators, according to the TTM. Or one might opt for a distinction between preintenders, who are (a) unaware of an issue, (b) aware but unengaged, or (c) still deciding.  Thus,  HAPA  is  not  a  puristic  stage  model, but  a  principle-based  framework  that  allows  for a  variety  of  approaches.  Evidence  from  intervention  studies  shows  good  results,  in  particular  for patients  with  various  chronic  illnesses  and  disabilities. Planning interventions and action control programs proved especially successful.


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