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  • research question- interventions therapies\npreventions\nprognosis\netiology- cause of the condition and risk factors(characteristics that make it more likely that they develope a condition) of condition\ndisgnosis\n
  • descriptive - observational characteristics, traits of individuals events behaviors phenomenon that you’re interested in\nexploration-observational correlational regression\nexperimental- qusi- exp studies, the study should be controlled and randomized (helps eliminate bias)\nBias-Systematic error that affects results\n
  • descriptive - observational characteristics, traits of individuals events behaviors phenomenon that you’re interested in\nexploration-observational correlational regression\nexperimental- qusi- exp studies, the study should be controlled and randomized (helps eliminate bias)\nBias-Systematic error that affects results\n
  • descriptive - observational characteristics, traits of individuals events behaviors phenomenon that you’re interested in\nexploration-observational correlational regression\nexperimental- qusi- exp studies, the study should be controlled and randomized (helps eliminate bias)\nBias-Systematic error that affects results\n
  • descriptive - observational characteristics, traits of individuals events behaviors phenomenon that you’re interested in\nexploration-observational correlational regression\nexperimental- qusi- exp studies, the study should be controlled and randomized (helps eliminate bias)\nBias-Systematic error that affects results\n
  • descriptive - observational characteristics, traits of individuals events behaviors phenomenon that you’re interested in\nexploration-observational correlational regression\nexperimental- qusi- exp studies, the study should be controlled and randomized (helps eliminate bias)\nBias-Systematic error that affects results\n
  • descriptive - observational characteristics, traits of individuals events behaviors phenomenon that you’re interested in\nexploration-observational correlational regression\nexperimental- qusi- exp studies, the study should be controlled and randomized (helps eliminate bias)\nBias-Systematic error that affects results\n
  • descriptive - observational characteristics, traits of individuals events behaviors phenomenon that you’re interested in\nexploration-observational correlational regression\nexperimental- qusi- exp studies, the study should be controlled and randomized (helps eliminate bias)\nBias-Systematic error that affects results\n
  • descriptive - observational characteristics, traits of individuals events behaviors phenomenon that you’re interested in\nexploration-observational correlational regression\nexperimental- qusi- exp studies, the study should be controlled and randomized (helps eliminate bias)\nBias-Systematic error that affects results\n
  • descriptive - observational characteristics, traits of individuals events behaviors phenomenon that you’re interested in\nexploration-observational correlational regression\nexperimental- qusi- exp studies, the study should be controlled and randomized (helps eliminate bias)\nBias-Systematic error that affects results\n
  • descriptive - observational characteristics, traits of individuals events behaviors phenomenon that you’re interested in\nexploration-observational correlational regression\nexperimental- qusi- exp studies, the study should be controlled and randomized (helps eliminate bias)\nBias-Systematic error that affects results\n
  • descriptive - observational characteristics, traits of individuals events behaviors phenomenon that you’re interested in\nexploration-observational correlational regression\nexperimental- qusi- exp studies, the study should be controlled and randomized (helps eliminate bias)\nBias-Systematic error that affects results\n
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  • : identifies association but cannot determine cause and effect\n
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  • Characterisitics or attributes of individiuals are measured\n Variables: observable concepts that can be measured directly\n Eg, joint range of motion; muscle strength; pain\n Constructs: non-observable concepts that must be measured indirectly\n Eg, IQ\n
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  • An independent variable is the variable you have control over, what you can choose and manipulate. It is usually what you think will affect the dependent variable. In some cases, you may not be able to manipulate the independent variable. It may be something that is already there and is fixed, something you would like to evaluate with respect to how it affects something else, the dependent variable like color, kind, time. \nExample: You are interested in how stress affects heart rate in humans. Your independent variable would be the stress and the dependent variable would be the heart rate. You can directly manipulate stress levels in your human subjects and measure how those stress levels change heart rate.\n
  • An independent variable is the variable you have control over, what you can choose and manipulate. It is usually what you think will affect the dependent variable. In some cases, you may not be able to manipulate the independent variable. It may be something that is already there and is fixed, something you would like to evaluate with respect to how it affects something else, the dependent variable like color, kind, time. \nExample: You are interested in how stress affects heart rate in humans. Your independent variable would be the stress and the dependent variable would be the heart rate. You can directly manipulate stress levels in your human subjects and measure how those stress levels change heart rate.\n
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Transcript

  • 1. Research Designs HSCI 313 Clinical Trials Protocols Margery Lockard, PT, PhD
  • 2. Lecture objectives
  • 3. Lecture objectives List and describe the basic types of research study designs
  • 4. Lecture objectives List and describe the basic types of research study designs List and describe the types of methods used in each research design
  • 5. Lecture objectives List and describe the basic types of research study designs List and describe the types of methods used in each research design Match the appropriate study design to a research question
  • 6. Research Designs Consumer or User of Clinical Research in making clinical decisions Conducting Clinical Research to produce new knowledge or applications
  • 7. The type of study designdepends on what you aretrying to find out…or, theresearch question dictatesthe study design So… What kind of designs are there?
  • 8. The taxonomy of study designs All studies Descriptive AnalyticSurveys/ Qualitative Case Reports/ Experimental Quasi- Non-Questionnaires Research Case Series Experimental Experimental/ Observational
  • 9. The taxonomy of study designs All studies Descriptive AnalyticSurveys/ Qualitative Case Reports/ Experimental Quasi- Non-Questionnaires Research Case Series Experimental Experimental/ Observational
  • 10. The taxonomy of study designs All studies Descriptive AnalyticSurveys/ Qualitative Case Reports/ Experimental Quasi- Non-Questionnaires Research Case Series Experimental Experimental/ Observational
  • 11. The taxonomy of study designs All studies Descriptive AnalyticSurveys/ Qualitative Case Reports/ Experimental Quasi- Non-Questionnaires Research Case Series Experimental Experimental/ Observational
  • 12. The taxonomy of study designsChapter 14 All studies Descriptive Analytic Surveys/ Qualitative Case Reports/ Experimental Quasi- Non- Questionnaires Research Case Series Experimental Experimental/ Observational
  • 13. The taxonomy of study designs Chapter 14 All studies Descriptive Analytic Surveys/ Qualitative Case Reports/ Experimental Quasi- Non- Questionnaires Research Case Series Experimental Experimental/ ObservationalAlso addressedin Chapter 15
  • 14. The taxonomy of study designs Chapter 14 All studies Descriptive Analytic Surveys/ Qualitative Case Reports/ Experimental Quasi- Non- Questionnaires Research Case Series Experimental Experimental/ ObservationalAlso addressedin Chapter 15
  • 15. The taxonomy of study designs Chapter 14 All studies Descriptive Analytic Surveys/ Qualitative Case Reports/ Experimental Quasi- Non- Questionnaires Research Case Series Experimental Experimental/ ObservationalAlso addressedin Chapter 15
  • 16. The taxonomy of study designs Chapters Chapter 14 10,11, and 13 All studies Descriptive Analytic Surveys/ Qualitative Case Reports/ Experimental Quasi- Non- Questionnaires Research Case Series Experimental Experimental/ ObservationalAlso addressedin Chapter 15
  • 17. The taxonomy of study designs Chapters Chapter 14 10,11, and 13 All studies Descriptive Analytic Surveys/ Qualitative Case Reports/ Experimental Quasi- Non- Questionnaires Research Case Series Experimental Experimental/ Observational Chapter 10Also addressedin Chapter 15
  • 18. The taxonomy of study designs Chapters Chapter 14 10,11, and 13 All studies Descriptive Analytic Surveys/ Qualitative Case Reports/ Experimental Quasi- Non- Questionnaires Research Case Series Experimental Experimental/ Observational Chapter 10 Chapter 11Also addressedin Chapter 15
  • 19. The taxonomy of study designs Chapters Chapter 14 10,11, and 13 All studies Descriptive Analytic Surveys/ Qualitative Case Reports/ Experimental Quasi- Non- Questionnaires Research Case Series Experimental Experimental/ Observational Chapter 10 Chapter 11 Chapter 13 (Exploratory)Also addressedin Chapter 15
  • 20. To Understand a Topic ofInterest, usually a series ofstudies are needed: Descriptive Studies  Observational Analytic  Exploratory Studies  Observational and Analytical  Identifies relationships and predictions  Experimental Studies  To determine cause and effect relationships
  • 21. To Understand an Topic of InterestWe Need A Series of Studies: Firstwe need… Descriptive Studies  Describe the characteristics of a group of individuals, phenomenon, events or behaviors of interest  Observational (not manipulating)  Examples:  What are the characteristics of adolescents with ACL injuries?  What is the “normal” strength of healthy individuals through the life span? (normative study)  Eg, How does strength change as an individual matures and then ages?  What is the “natural history” of a disease?  Provides the basic information needed to classify individuals or groups
  • 22. To Understand an Area WeNeed A Series of Studies,Second we need.. Exploratory Research  Investigates relationships among 2+ factors  human attributes, environmental characterisitics)  The factors of interest are observed as they naturally occur to see how they inter-relate (factors are not manipulated)  Eg, What is the relationship between SAT scores and college GPA at the end of the 1st yr of college? At college graduation?  Eg, What factors in the application to graduate school predict the best graduate school outcome?  Correlational studies  Predictive studies
  • 23. In Exploratory research designs…
  • 24. In Exploratory research designs… No manipulation of variables
  • 25. In Exploratory research designs… No manipulation of variables Tests relationships between variables
  • 26. In Exploratory research designs… No manipulation of variables Tests relationships between variables Used to predict effect of one variable on another
  • 27. In Exploratory research designs… No manipulation of variables Tests relationships between variables Used to predict effect of one variable on another Time . . . . what happens to variables over time? o Prospective o Retrospective o Cross-sectional
  • 28. Understanding time in non-
  • 29. To Understand an Area of interest WeNeed A Series of Studies, lastly weneed a series of… Experimental Studies  Evaluate cause and effect  Researcher manipulates certain variables to determine what the effect is on other variables  Often referred to as Clinical Trials or Randomized Controlled Trials (RCTs) o Used to test the effectiveness of various therapies or treatments (interventions) o Compares groups o Between group trials o Within group trials
  • 30. Researcher Manipulates FactorsObservationalMethods 12
  • 31. Researcher Manipulates FactorsObservationalMethods Level 1 Questions 12
  • 32. Researcher Manipulates Factors Level 2 QuestionsObservationalMethods Level 1 Questions 12
  • 33. Researcher Level 3 Manipulates Factors Questions Level 2 QuestionsObservationalMethods Level 1 Questions 12
  • 34. What are the primary differencesbetween descriptive and analyticdesigns?
  • 35. What are the primary differences between descriptive and analytic designs? Descriptive o Attempts to give us a picture of what is going on in a population o Identify prevalence or incidence of disease or condition o Understand the experiences, attitudes, social norms, and/or beliefs of a population
  • 36. What are the primary differences between descriptive and analytic designs? Descriptive  Analytic o Attempts to give us a picture of what is going on in a population o Identify prevalence or incidence of disease or condition o Understand the experiences, attitudes, social norms, and/or beliefs of a population
  • 37. What are the primary differences between descriptive and analytic designs? Descriptive  Analytic o Attempts to give us a o Attempts to quantify picture of what is relationships going on in a population o Identify prevalence or incidence of disease or condition o Understand the experiences, attitudes, social norms, and/or beliefs of a population
  • 38. What are the primary differences between descriptive and analytic designs? Descriptive  Analytic o Attempts to give us a o Attempts to quantify picture of what is relationships going on in a o Used to explore population associations between o Identify prevalence or variables incidence of disease or condition o Understand the experiences, attitudes, social norms, and/or beliefs of a population
  • 39. What are the primary differences between descriptive and analytic designs? Descriptive  Analytic o Attempts to give us a o Attempts to quantify picture of what is relationships going on in a o Used to explore population associations between o Identify prevalence or variables incidence of disease or o Used to examine effect condition of an intervention on an o Understand the outcome experiences, attitudes, social norms, and/or beliefs of a population
  • 40. What are the primary differences between descriptive and analytic designs? Descriptive  Analytic o Attempts to give us a o Attempts to quantify picture of what is relationships going on in a o Used to explore population associations between o Identify prevalence or variables incidence of disease or o Used to examine effect condition of an intervention on an o Understand the outcome experiences, attitudes, o Used to examine effect social norms, and/or of an exposure on an beliefs of a population outcome
  • 41. Qualitative v. Quantitative Research Methods Describes the type of data that is collected Quantitative research collects…  Numerical data  Characterisitics or attributes of individiuals are measured
  • 42. Qualitative v. Quantitative Research Methods Describes the type of data that is collected Quantitative research collects…  Numerical data  Characterisitics or attributes of individiuals are measured Qualitative research collects  Narrative data  Words of the subjects in Interview or Focus Group:  Description of the subject of interest “lived experiences”  Helps us to understand complex social phenomenon
  • 43. Qualitative v. Quantitative Research Methods Describes the type of data that is collected Quantitative research collects…  Numerical data  Characterisitics or attributes of individiuals are measured Qualitative research collects  Narrative data  Words of the subjects in Interview or Focus Group:  Description of the subject of interest “lived experiences”  Helps us to understand complex social phenomenon Mixed Methods  Qualitative and quantitative data
  • 44. Analytic ResearchDesignsExperimentalQuasi-experimentalNon-Experimental/Observational
  • 45. Experimental ResearchDesigns: Terms you must
  • 46. Experimental ResearchDesigns: Terms you must Variables or Constructs  Attributes or characteristics of the thing that is being studied  Variables: can be directly measured  Constructs: can not be directly measured  Examples:  Joint range of motion?  Muscle strength?  Obesity?  Intelligence?  Operational Definitions
  • 47. WHY MUST WE DEFINE OUR VARIABLES? 17
  • 48. Variables: Dependent variable…  What you are trying to learn about or explain  What you measure  What is expected to change or vary in response to the IV  The presumed effect
  • 49. Variables: Dependent variable…  What you are trying to learn about or explain  What you measure  What is expected to change or vary in response to the IV  The presumed effect Independent variable  What you manipulate to see how it effects the dependent variable  The factor that you hypothesize influences or causes the thing you are interested  The presumed cause
  • 50. Independent Variables Active variables Attribute variables Extraneous variables
  • 51. Experimental research designsThe simplest RCT: Pretest-Posttest control group design Populationrecruitment
  • 52. Experimental research designsTwo group pretest-posttest design (control v. no control)
  • 53. Experimental research designsTwo group pretest-posttest design (control v. no control)
  • 54. Many other experimental designsexist and may better suit certain researchquestions.
  • 55. Many other experimental designsexist and may better suit certain researchquestions. Post-test only randomized designs
  • 56. Many other experimental designsexist and may better suit certain researchquestions. Post-test only randomized designs Multi-factorial designs o Two-way (2 independent variables) o Three-way (3 independent variables)
  • 57. Many other experimental designsexist and may better suit certain researchquestions. Post-test only randomized designs Multi-factorial designs o Two-way (2 independent variables) o Three-way (3 independent variables) Repeated measures designs (within-subjects)
  • 58. Many other experimental designsexist and may better suit certain researchquestions. Post-test only randomized designs Multi-factorial designs o Two-way (2 independent variables) o Three-way (3 independent variables) Repeated measures designs (within-subjects) Cross-over designs
  • 59. Many other experimental designsexist and may better suit certain researchquestions. Post-test only randomized designs Multi-factorial designs o Two-way (2 independent variables) o Three-way (3 independent variables) Repeated measures designs (within-subjects) Cross-over designs See Chapter 10 for more experimental designs
  • 60. Quasi-experimental designs areoften excellent alternatives to trueexperiments.
  • 61. Quasi-experimental designs areoften excellent alternatives to trueexperiments.  Very similar in structure to experimental designs
  • 62. Quasi-experimental designs areoften excellent alternatives to trueexperiments.  Very similar in structure to experimental designs  Degree of control is reduced
  • 63. Quasi-experimental designs areoften excellent alternatives to trueexperiments.  Very similar in structure to experimental designs  Degree of control is reduced  Lack random assignment to groups
  • 64. Quasi-experimental designs areoften excellent alternatives to trueexperiments.  Very similar in structure to experimental designs  Degree of control is reduced  Lack random assignment to groups or
  • 65. Quasi-experimental designs areoften excellent alternatives to trueexperiments.  Very similar in structure to experimental designs  Degree of control is reduced  Lack random assignment to groups or  Lack comparison groups all together
  • 66. Quasi-experimental designs areoften excellent alternatives to trueexperiments.  Very similar in structure to experimental designs  Degree of control is reduced  Lack random assignment to groups or  Lack comparison groups all together  Again… many, many different forms exist
  • 67. Quasi-experimentaldesigns… The simplest quasi-experimental study: the one group pre-post test
  • 68. Quasi-experimental designs Time series Designs
  • 69. Quasi-experimental designs Time series Designs
  • 70. Quasi-experimental designs Non-equivalent control group designs o Patients from clinics o Students from classes
  • 71. Quasi-experimental designs Non-equivalent control group designs o Patients from clinics o Students from classes
  • 72. Quasi-experimental designs Non-equivalent control group designs o Patients from clinics o Students from classes
  • 73. Non-ExperimentalDesigns Cohort Studies Case-control studies
  • 74. ProspectiveNon-ExperimentalDesigns•Cohort studies•Always followsubjectsforward in time Retrospective
  • 75. The Case-Control StudyNon- The caseExperimental controlDesigns:•Case ControlStudies
  • 76. Non-Experimental designs…more
  • 77. Non-Experimental designs…more Correlational Studies o Extent to which a variable moves in the same or opposite direction with another variable o Must interpret strong correlations with caution o Correlation does not imply causation
  • 78. Non-Experimental designs…more Correlational Studies o Extent to which a variable moves in the same or opposite direction with another variable o Must interpret strong correlations with caution o Correlation does not imply causation
  • 79. Non-Experimental designs…more Correlational Studies o Extent to which a variable moves in the same or opposite direction with another variable o Must interpret strong correlations with caution o Correlation does not imply causation Prediction Studies o Designed to predict an outcome o Used to develop models for clinical decision making o Use multiple regression analysis to establish