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HEALTHCARE RESEARCH METHODS: Experimental Studies and Qualitative Studies

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HEALTHCARE RESEARCH METHODS: Experimental Studies and Qualitative Studies

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HEALTHCARE RESEARCH METHODS: Experimental Studies and Qualitative Studies

  1. 1. PHC215 By Dr. Khaled Ouanes Ph.D. E-mail: k.ouanes@seu.edu.sa Twitter: @khaled_ouanes INTRODUCTION TO HEALTHCARE RESEARCH METHODS
  2. 2. Experimental Studies
  3. 3. An experimental study assigns participants to intervention and control groups in order to examine whether an intervention causes an intended outcome. Because the researcher assigns participants to receive a particular exposure, the exact timing, dose, duration, and frequency of the exposure are known.
  4. 4. Framework for an Experimental Study.
  5. 5. Randomized Controlled Trials (RCTs) In a randomized controlled trial (RCT): Some participants are randomly assigned to an active intervention group The remaining participants are assigned to a control group All participants from both groups are followed forward in time to see who has a favorable outcome and who does not
  6. 6. Describing the Intervention The research plan should carefully define: What the intervention will be Where and how participants will receive the intervention When, how often, and for what duration participants will receive the intervention Eligibility and aptness criteria for participants
  7. 7. Defining Outcomes Most experimental studies are superiority trials that aim to demonstrate that a new intervention is “better” than some type of control. Because the term “better” can be defined in so many ways, the researcher must beforehand and carefully define what constitutes a favorable outcome for the experiment.
  8. 8. Types of Success
  9. 9. Examples of Favorable Outcomes
  10. 10. Selecting Controls Experimental studies usually assign some participants to the active intervention and the remainder to a control group. SO WHAT TYPES OF CONTROLS CAN WE HAVE?
  11. 11. 1. The most typical control is a placebo, an inactive comparison that is similar to the therapy being tested 2. Sometimes the new therapy is compared to some existing “industry standard of care” or other therapy 3. Sometimes varying doses and durations of a therapy may be compared to one another Selecting Controls
  12. 12. Examples of Types of Controls
  13. 13. Examples of Types of Controls
  14. 14. Hawthorne bias Hawthorne effect: (observer effect) is a type of reactivity in which participants in a study may change their behavior for the better simply because they know they are being observed This may interfere with the accurate measurement of the impact of the new intervention.
  15. 15. Blinding Blinding or masking: Participants in an experimental study do not know whether they are in the active intervention group or the control group. Blinding minimizes information bias
  16. 16. Blinding There are 2 main cases:  In a single-blind study, participants are unaware of their exposure status  In a double-blind study, neither the participants nor the persons assessing the participants’ health status know which participants are in the active and control groups.
  17. 17. Randomization A variety of approaches can be used to randomly allocate participants to an active intervention group or a control group: Simple randomization Block randomization Stratified randomization
  18. 18. Examples of Types of Randomization Strata: Homogeneous subgroups of members in the population
  19. 19. Ethical Considerations Experimental studies involve a particularly high level of ethical risk because the researcher assigns participants to exposures that the participants do not choose and may have been unlikely to encounter in normal life had they not volunteered to participate in a research project.
  20. 20. Ethical Principles Clinical Equipoise or equipoise principal: It provides the ethical basis for medical research that involves assigning patients to different treatments of a clinical trial. The term was first used by Benjamin Freedman in 1987. It states that experimental research should be conducted only when there is genuine uncertainty about which treatment will work better
  21. 21. Ethical Principles Distributive justice: infers that the source population must be an appropriate and non- exploitative one Beneficence (doing good) and non-maleficence (do not harm): researchers must balance the likely benefits and risks of the study. Otherwise the study should not be conducted.
  22. 22. Respect for persons: Participants must volunteer for a study without being unduly influenced by the prospect of being compensated for their participation Participants must be able to understand what it means to be a research subject, including the possibility of being assigned to a control group instead of the new intervention Ethical Principles
  23. 23. Examples of Ethical Issues to Consider When Planning an Experimental Study
  24. 24. Analysis Experimental studies use many of the same measures of association that cohort studies do:  Relative rates (RRs)  Attributable risks (ARs, AR%s)  Measures of survival Experimental studies use these measures to examine the impact of an assigned exposure on the likelihood of having either a favorable or unfavorable outcome.
  25. 25. Analysis: Efficacy Efficacy: the proportion of individuals in the control group who experience an unfavorable outcome who could have been expected to have a favorable outcome had they been in the active group instead of control. A high efficacy is an indicator that an intervention is successful.
  26. 26. Analysis: NNT Number needed to treat (NNT): the expected number of people who would have to receive a treatment to prevent an unfavorable outcome in one person (or, alternately stated, to achieve a favorable outcome in one person) A small NNT indicates a more effective intervention.
  27. 27.  If a drug is intended to prevent stroke and has an NNT of 5, then 5 people have to take the drug for one year (or some other chosen time span) to prevent one of the 5 from having a stroke.  If a drug has an NNT of 100, it means that 100 people have to take the drug to prevent one of the 100 from having a stroke. Analysis: NNT
  28. 28. Stratification of patients for efficacy can substantially reduce the number needed to treat for benefit. Matthews, P. M. et al (2013)
  29. 29. In the example depicted in the previous slide, 22% of patients respond to a given treatment, so approximately 5 patients need to be treated to benefit one patient (NNT=5). If the population is stratified to enrich the treated population with responders (identified through testing), the number needed to treat for benefit will decrease. In this example, a stratification approach with 90% sensitivity and specificity is assumed.
  30. 30. Efficacy & Number Needed to Treat (NNT)
  31. 31. Analytic Frameworks Treatment-received approach: limit analysis to the participants who were fully compliant with their assigned intervention Treatment-assigned approach (intention-to- treat approach): includes all participants even if they were not fully compliant with their assigned intervention
  32. 32. Flow of Participants in an Experimental Study
  33. 33. KeyCharacteristicsof Experimentalstudies
  34. 34. Screening & Diagnostic Tests The goal of some studies is to compare two tests that are supposed to measure the same thing, such as comparing the results of an antibody test for cancer to biopsy results
  35. 35. Sensitivity = Of those who have the disease, what % test positive? Specificity = Of those who do not have the disease, what % test negative? Screening & Diagnostic Tests
  36. 36. Positive predictive value (PPV) = Of those who test positive, what % actually have the disease? Negative predictive value (NPV) = Of those who test negative, what % actually do not have the disease? Screening & Diagnostic Tests
  37. 37. Test Results
  38. 38. Tests of Agreement  Tests of inter-observer agreement (concordance) can be used to determine the extent of agreement between two assessors who are evaluating the same study participants Example: a measurement known as the kappa statistic can indicate whether two radiologists examining the same set of X-rays reach the same conclusion about the presence or absence of a fracture more or less often than can be expected by chance
  39. 39. Qualitative Studies
  40. 40. Qualitative Study Methods A qualitative study looks for the themes and meanings that emerge from the observation and evaluation of a situation or context. Researchers have intense contact with a selected group of informants.
  41. 41. Examples of Approaches  Phenomenology: seeks to understand how participants understand, interpret, and find meaning in their own unique life experiences and feelings  Grounded theory: an inductive reasoning process that uses observations to develop general theories that explain human behavior  Ethnography: aims to develop an insider’s view (an emic perspective) of how members of a particular Ethnic or cultural group see their world
  42. 42. Examples of Techniques  In-depth and semi-structured interviews of individuals use open-ended questions to explore viewpoints. The interviewer is allowed to probe for more details about any response in order to gain fuller understanding of the participant’s experiences and perspectives.  Interviews are often supplemented by other methods, such as participant diaries or journals.
  43. 43. Focus groups of about 4 to 12 people are moderated discussions led by a facilitator from the research team. The facilitator encourages participants to interact with one another and to clarify their individual and shared perspectives. Examples of Techniques
  44. 44. Examples of Analytic Techniques  The analysis of qualitative data usually involves coding and classifying observations and deriving major and minor themes from the groups of observations.  Reports of the findings of qualitative studies often incorporate quotations that express participants’ perspectives and experiences in their own words.
  45. 45. Consensus Methods The goal of some studies is to identify areas of consensus and areas of contention among individuals who are experts on a particular topic and/or a particular community or organization.
  46. 46. Delphi Method The Delphi method is a structured decision-making and forecasting process in which participants engage in several rounds of:  Completing individual questionnaires  A facilitator summarizing and sharing the responses  Panelists reconsidering their perspectives after reflecting on the opinions expressed by others The goal is for each iteration to move the panel of experts closer to agreement.
  47. 47. DelphiMethod
  48. 48. Program Evaluation  Program evaluation includes a variety of approaches for provide feedback about what is working well and what can and should be improved  The evaluation approach must match the goals of the assessment  After gathering evidence from a variety of sources, practical suggestions are made based on the conclusions of the assessment
  49. 49. Evidence is reviewed and categorized using a framework like SWOT:  Strengths (internal organizational strengths)  Weaknesses (internal organizational limitations)  Opportunities (external strengths)  Threats (external limitations, which might be political, economic, sociocultural, technological, environmental, or legal) Program Evaluation
  50. 50. ProgramEvaluation
  51. 51. A similar process can be used as a component of other forms of evaluative research, such as: Needs assessment. Cost-effectiveness analysis Health services research Program Evaluation
  52. 52. PHC215 By Dr. Khaled Ouanes Ph.D. E-mail: k.ouanes@seu.edu.sa Twitter: @khaled_ouanes HEALTHCARE RESEARCH METHODS Based on the textbook of introduction to health research methods – K.H. Jacobsen

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