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RESEARCH DESIGN WHAT? DESIGN: A PLAN TO CONDUCT THE RESEARCH, TEST THE HYPOTHESES OR ANSWER THE RESEARCH QUESTIONS.

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Presentation on theme: "RESEARCH DESIGN WHAT? DESIGN: A PLAN TO CONDUCT THE RESEARCH, TEST THE HYPOTHESES OR ANSWER THE RESEARCH QUESTIONS."— Presentation transcript:

1 RESEARCH DESIGN WHAT? DESIGN: A PLAN TO CONDUCT THE RESEARCH, TEST THE HYPOTHESES OR ANSWER THE RESEARCH QUESTIONS.

2 RESEARCH DESIGN WHY? RESEARCHER WANTS TO CONTROL THE QUALITY OF THE RESEARCH BY KEEPING CONDITIONS UNIFORM. WANTS TO AVOID BIAS AND ENSURE REPLICATION.

3 RESEARCH DESIGN HOW? QUESTION OFTEN LEADS TO DESIGN. SOME QUESTIONS ARE NOT RESEARCH ABLE. WHAT KINDS OF VARIABLES DO NOT LEND THEMSELVES TO INTERVENTIONS OR EXPERIMENTS?

4 RESEARCH DESIGN OTHER FACTORS LEADING TO DESIGN SELECTION 1. ACCURACY: ALL ASPECTS OF STUDY SYSTEMATICALLY & LOGICALLY FLOW FROM PROBLEM STATEMENT. 2. FEASIBILITY: CAN PROJECT BE DONE? SUBJECTS, DATA, COSTS, TIME, FACILITY & EQUIPMENT, ETHICS & RESEARCHER EXPERIENCE?

5 RESEARCH DESIGN 3. CONTROL: HOLD CONDITIONS OF STUDY CONSTANT, ESTABLISH SPECIFIC SAMPLING CRITERIA. CONTROL RULES OUT EXTRANEOUS OR MEDIATING VARIABLES: ONES THAT INTERFERE WITH INDEPENDENT VARIABLE, e.g. AGE (MATURATION EFFECT), OTC MEDS IN ANTIBIOTIC STUDY.

6 RESEARCH DESIGN HOW TO CONTROL FOR MEDIATING VARIABLES 1) HOMOGENOUS SAMPLING - GENERALIZE FINDINGS ONLY TO THIS POPULATION

7 RESEARCH DESIGN HOW TO CONTROL FOR MEDIATING VARIABLES 2) USE CONSISTENT DATA COLLECTION TECHNIQUES: COOKBOOK MEASURES, RATER RELIABILITY, EQUIPMENT. ALL CALIBRATED.

8 RESEARCH DESIGN HOW TO CONTROL FOR MEDIATING VARIABLES 3) MANIPULATE INDEPENDENT VARIABLE: CONTROL GROUP HAS NO MANIPULATION, BUT “USUAL CONDITIONS” REMAIN CONSTANT.

9 RESEARCH DESIGN HOW TO CONTROL FOR MEDIATING VARIABLES 4) RANDOMIZATION IN SELECTION OF SUBJECTS AND ALLOCATION OF TREATMENT (INDEPENDENT VARIABLE).

10 RESEARCH DESIGN NON-EXPERIMENTAL DESIGNS DO NOT MANIPULATE INDEPENDENT VARIABLE & DO NOT HAVE EITHER AN EXPERIMENTAL OR CONTROL GROUP. USUALLY CALLED THE STUDY GROUP. DESIGN HAS TO FIT THE QUESTION.

11 RESEARCH DESIGN EXPERIMENTAL DESIGNS MANIPULATE THE INDEPENDENT VARIABLE & ALWAYS HAVE A CONTROL AND AN EXPERIMENTAL GROUP.

12 RESEARCH DESIGN ORDER OF RIGOUR OF DESIGNS 1. NON-EXPERIMENTAL A. EXPLORATORY DESIGN B. CORRELATIONAL DESIGN 2. QUASI-EXPERIMENTAL 3. EXPERIMENTAL

13 RESEARCH DESIGN 1. NON-EXPERIMENTAL A. EXPLORATORY DESIGN LITTLE LITERATURE EXISTS. RESEARCHER WANTS TO DESCRIBE OR CATEGORIZE THE PHENOMENA. NO CONTROL OF EXTRANEOUS VARIABLES.

14 RESEARCH DESIGN 1. NON-EXPERIMENTAL B. CORRELATIONAL DESIGN MORE LITERATURE EXISTS. RESEARCHER WANTS TO LOOK AT RELATIONSHIP BETWEEN TWO VARIABLES. SOME CONTROL OF EXTRANEOUS VARIABLES.

15 RESEARCH DESIGN 2. QUASI-EXPERIMENTAL MANIPULATE INDEPENDENT VARIABLE, BUT OFTEN MISSING CONTROL GROUP OR BASELINE MEASUREMENT.

16 RESEARCH DESIGN 4. EXPERIMENTAL MANIPULATE INDEPENDENT VARIABLE. RANDOM SELECTION & ALLOCATION (CONTROL GROUP). BASELINE MEASURES. STRICT CONTROLS.

17 RESEARCH DESIGN NONEXPERIMENTAL DESIGNS USED TO DESCRIBE PHENOMENA. NO MANIPULATION OF INDEPENDENT VARIABLE. EXPLORE RELATIONSHIPS OF DIFFERENCES. CAN LEAD TO MORE RIGOROUS DESIGNS. ALSO REQUIRES CLEAR CONCISE PROBLEM STATEMENT.

18 RESEARCH DESIGN 1. NON-EXPERIMENTAL A. DESCRIPTIVE/EXPLORATORY SURVEYS INTERESTED IN OPINIONS, ATTITUDES & FACTS. HOW MANY PEOPLE WILL VOTE FOR WHICH PARTY? WHAT SHOULD THE BASIC ENTRY LEVEL PREPARATION OF SOCIAL WORKERS BE?

19 RESEARCH DESIGN A. DESCRIPTIVE/EXPLORATORY SURVEYS METHODS: INCLUDE EITHER QUESTIONNAIRE (MAILED, COMPUTER) OR INTERVIEW (PHONE, IN-PERSON).

20 RESEARCH DESIGN PROS OF DESCRIPTIVE/ EXPLORATORY SURVEYS LENDS ITSELF TO RANDOM SELECTION & SO ACCURACY CAN BE MEASURED. INEXPENSIVE. CAN GATHER LOT OF INFORMATION.

21 RESEARCH DESIGN CONS OF DESCRIPTIVE EXPLORATORY SURVEYS DESCRIPTION OF VARIABLES OBTAINS BREATH NOT DEPTH OF INFORMATION. MAY BE EXPENSIVE. REQUIRES RESEARCH EXPERTISE IN SAMPLING TECHNIQUES, QUESTIONNAIRE CONSTRUCTION, INTERVIEWING & DATA ANALYSIS.

22 RESEARCH DESIGN 2. NON-EXPERIMENTAL B. CROSS-SECTIONAL STUDIES COLLECT DATA AT ONLY ONE POINT IN TIME. CAN BE DONE ON MORE THAN ONE GROUP. OFTEN A SURVEY.

23 RESEARCH DESIGN PROS OF CROSS-SECTIONAL STUDIES LESS EXPENSIVE RESULTS READILY AVAILABLE NO MATURATION, MORTALITY THREATS.

24 RESEARCH DESIGN CONS OF CROSS-SECTIONAL STUDIES CAN’T TELL IF INDEPENDENT VARIABLE PRECEDED DEPENDENT VARIABLE.

25 RESEARCH DESIGN 1. NON-EXPERIMENTAL C. LONGITUDINAL STUDY DATA FROM SAME GROUP IS COLLECTED AT DIFFERENT POINTS IN TIME. FOLLOW COHORT. E.G. FRAMINGHAM STUDY. CANADA POPULATION HEALTH STUDY. CAN BE RETROSPECTIVE. USUALLY IS PROSPECTIVE.

26 RESEARCH DESIGN PROS OF LONGITUDINAL STUDY APPROPRIATE WHEN STUDYING CHRONIC DISEASES OR CONDITIONS WITH LATENT ATTRIBUTES. EACH SUBJECT ACTS AS OWN CONTROL CAN SPOT EARLY TRENDS.

27 RESEARCH DESIGN CONS OF LONGITUDINAL STUDY EXPENSIVE LOSS TO FOLLOW-UP MORTALITY) TESTING EFFECT

28 RESEARCH DESIGN 1. NON-EXPERIMENTAL D. CROSS-SECTIONAL STUDIES COLLECT DATA AT ONLY ONE POINT IN TIME. CAN BE DONE ON MORE THAN ONE GROUP. OFTEN A SURVEY.

29 RESEARCH DESIGN 1. NONEXPERIMENTAL DESIGNS E. CORRELATIONAL DESIGN (EX POST FACTO) NOT INTERESTED IN TESTING WHETHER ONE VARIABLE CAUSES ANOTHER OR HOW DIFFERENT ONE VARIABLE IS FROM ANOTHER.

30 RESEARCH DESIGN ASKS: AS ONE VARIABLES VARIES, WHAT HAPPENS TO ANOTHER VARIABLE? IN WHAT DIRECTION DOES CHANGE OCCUR? HOW DOES MATERNAL ANXIETY EFFECT CHILDREN’S ANXIETY? DOES  MATERNAL ANXIETY RELATE TO  OR  IN CHILDREN’S ANXIETY?

31 RESEARCH DESIGN PROS OF CORRELATION DESIGNS FLEXIBILE WHEN INVESTIGATING COMPLEX RELATIONSHIPS. EFFICIENT & ALLOWS COLLECTION OF LARGE AMOUNTS OF DATA.

32 RESEARCH DESIGN CONS OF CORRELATIONAL STUDIES NO MANIPULATION NO RANDOM SELECTION, DEALS WITH PRE-EXISTING GROUPS. NO CAUSALITY.

33 RESEARCH DESIGN 1 NON-EXPERIMENTAL F. COMPARATIVE DESIGN OR CASE CONTROL STUDY HYPOTHESIZE ABOUT A RELATIONSHIP & TEST TO SEE IF IT EXISTS. DO NOT RANDOMLY ALLOCATE SUBJECTS TO GROUPS. DO NOT MANIPULATE.

34 RESEARCH DESIGN E. COMPARATIVE DESIGN OR CASE CONTROL STUDY FIND SUBJECTS WITH DISEASE. MATCH WITH OTHER SUBJECTS WITHOUT DISEASE. COMPARE EXPOSURE BACK IN TIME. USUALLY RETROSPECTIVE.

35 RESEARCH DESIGN PROS OF CASE CONTROL q EFFICIENT q HIGH LEVEL OF CONTROL.

36 RESEARCH DESIGN CONS OF CASE CONTROL DO NOT RANDOMLY ALLOCATE DO NOT MANIPULATE. NO CAUSALITY, CAN NOT RULE OUT COMPETING HYPOTHESES.

37 RESEARCH DESIGN COMPARATIVE DESIGN OR CASE CONTROL STUDY GROUP AO 1 --------------------------------------------- GROUP BO 1

38 RESEARCH DESIGN 2. QUASI-EXPERIMENTAL DESIGNS STILL INTERESTED IN CAUSE AND EFFECT; HOWEVER BECAUSE THEY ARE LESS RIGOROUS, THEY ARE PRONE TO BIASES OR THREATS TO INTERNAL VALIDITY.

39 RESEARCH DESIGN 2. QUASI-EXPERIMENTAL DESIGNS ALWAYS HAVE MANIPULATION. USUALLY LACKS RANDOM ALLOCATION. MAY LACK CONTROL GROUP.

40 RESEARCH DESIGN 2. QUASI-EXPERIMENTAL DESIGNS A. NON-EQUIVALENT CONTROL GROUP DESIGN NONEQUIVALENT BECAUSE GROUPS WERE NOT FORMED BY RANDOM ALLOCATION. HAS MANIPULATION. CAN HAVE PRETEST AND/OR POST- TEST.

41 RESEARCH DESIGN OFTEN USED WITH TWO HOSPITAL WARDS WITH PATIENTS WITH SIMILAR DIAGNOSES. ONE DOESN’T ABANDON A DESIGN. ONE ANTICIPATES THE THREATS AND PLANS HOW TO ADDRESS THEM.

42 RESEARCH DESIGN A. NON-EQUIVALENT CONTROL GROUP DESIGN (POST-TEST ONLY ) GROUP AX 1 O 1 ----------------------------- GROUP BX 1 O 1

43 RESEARCH DESIGN A. NON-EQUIVALENT CONTROL GROUP DESIGN (PRETEST- POSTTEST) GROUP AO 1 XO 2 ----------------------------- GROUP BO 1 O 2

44 RESEARCH DESIGN A. NON-EQUIVALENT CONTROL GROUP DESIGN THREATS SELECTION (EQUIVALENCE AT BASELINE), MATURATION, TESTING MORTALITY:

45

46 RESEARCH DESIGN QUASI-EXPERIMENTAL DESIGNS: 3. TIME SERIES NON EQUIVALENT OR NO GROUPS. MEASURE PRE-TEST SEVERAL TIMES THEN DO MANIPULATION. AND DO SEVERAL POST-TESTS

47 RESEARCH DESIGN 3. TIME SERIES GROUP A O 1 O 2 O 3 O 4 X O 5 O 6 O 7 O 8

48 RESEARCH DESIGN 3. TIME SERIES THREATS MATURATION EFFECT: DEPENDENT VARIABLE MAY CHANGE NATURALLY OVER TIME. MEASUREMENT: INTERVENTION FADE OVER TIME? SELECTION. MORTALITY.

49 RESEARCH DESIGN PROS OF QUASI-EXPERIMENTAL DESIGNS PRACTICAL FEASIBLE: WHEN YOU CAN’T ETHICALLY ASSIGN PEOPLE TO NOXIOUS INTERVENTION: CANCER. GENERALIZABLE

50 RESEARCH DESIGN CONS OF QUASI-EXPERIMENTAL DESIGNS LACK OF RIGOR INCREASED THREATS TO INTERNAL VALIDITY

51 RESEARCH DESIGN 3. EXPERIMENTAL DESIGNS OFTEN LAY PEOPLE THINK THAT WHEN A STATISTICAL ASSOCIATION IS FOUND, THAT MEANS CAUSALITY. THERE ARE SIGNIFICANTLY MORE BLUED-EYED MURDERERS THAN BROWN-EYED. ALL BLUE EYED PEOPLE KILL?

52 RESEARCH DESIGN 3. EXPERIMENTAL DESIGNS CAUSALITY 1. STRENGTH OF ASSOCIATION 2. DOSE-RESPONSE RELATIONSHIP 3. CONSISTENCY OF ASOCIATION 4.TEMPORALLY CORRECT ASSOCIATION 5. SPECIFICITY OF ASSOCIATION 6.COHERENCE WITH EXISTING KNOWLEDGE 1

53 RESEARCH DESIGN EXPERIMENTAL DESIGN HAS 3 CHACTERISTICS 1) RANDOM ASSIGNMENT (major difference between quasi & experimental), 2) CONTROL, AND 3) MANIPULATION OF INDEPENDENT VARIABLE.

54 RESEARCH DESIGN 3. EXPERIMENTAL DESIGNS i. RANDOM ASSIGNMENT: SUBJECTS ASSIGNED TO GROUP PURELY ON BASIS OF CHANCE. EACH SUBJECT HAS EQUAL OR KNOWN PROBABILITY OF BEING ASSIGNED TO ANY GROUP. ESSENTIAL TO ELIMINATE SYSTEMATIC BIAS THAT MAY EFFECT DEPENDENT VARIABLE.

55 RESEARCH DESIGN i. RANDOM ASSIGNMENT: HELPS TO ASSURE THAT INTERVENING VARIABLES ARE EQUALLY DISTRIBUTED AMONG GROUPS, E.G. AGE, PROGNOSIS. TO ENSURE THAT RANDOMIZATION HAS OCCURED, YOU ANALYZE CHARACTERISTICS OF TWO GROUPS AND REPORT THE FINDINGS.

56 RESEARCH DESIGN 3. EXPERIMENTAL DESIGNS i. RANDOM ASSIGNMENT HOW IS RANDOM SELECTION DIFFERENT FROM RANDOM ASSIGNMENT?

57 RESEARCH DESIGN 3. EXPERIMENTAL DESIGNS ii. CONTROL MANIPULATING INDEPENDENT VARIABLE, ADHERING TO PROTOCOLS, AND USING COMPARISON GROUPS.

58 RESEARCH DESIGN 3. EXPERIMENTAL DESIGNS iii. MANIPULATION INDEPENDENT VARIABLE IS THE MANIPULATION. IN HEALTH SCIENCES THIS IS OFTEN AN EDUCATIONAL PROGRAM.

59 RESEARCH DESIGN ANTECEDENT VARIABLE: OCCURS BEFORE STUDY BUT MAY EFFECT DEPENDENT VARIABLE, E.G. SES, GENDER, RACE. INTERVENING VARIABLE: OCCURS DURING STUDY & MIGHT EFFECT DEPENDENT VARIABLE. E.G. PROVINCIAL PSYCHIATRIC HOSPITAL CLOSURES.

60 RESEARCH DESIGN 1. TRUE EXPERIMENT (RANDOMIZED CLINICAL/CONTROL TRIAL RCT). SUBJECTS RANDOMLY ASSIGNED TO EXPERIMENTAL/CONTROL GROUP. MAY HAVE PRE-TEST, BUT DEFINITELY HAVE POST-TEST MEASURES. WHY A CONTROL GROUP? HOW DO YOU KNOW GROUPS ARE THE SAME?

61 RESEARCH DESIGN RANDOMIZED CLINICAL TRIAL WHY HAVE A PRE-TEST? WHY HAVE A POST-TEST? WHY RANDOMLY ASSIGN? HOW BIG A PROBLEM IS IT IF PATIENTS ARE NOT RANDOMLY SELECTED?

62 RESEARCH DESIGN 3. EXPERIMENTAL DESIGNS ii. SOLOMON FOUR GROUP DESIGN BECAUSE YOU WANT TO PRE-TEST & POST-TEST WITH SAME INSTRUMENT IN SHORT PERIOD OF TIME, TESTING EFFECTS ARE AN INTERNAL VALIDITY THREAT. TO OVERCOME THIS, USE A SOLOMON FOUR GROUP DESIGN.

63 RESEARCH DESIGN 3. EXPERIMENTAL DESIGNS ii. SOLOMON FOUR GROUP DESIGN RANDOMLY ASSIGN TO 4 GROUPS, ONLY GIVE PRE-TEST TO TWO GROUPS, GIVE POST-TEST TO ALL. WHAT DOES THIS ALLOW YOU TO SAY?

64 RESEARCH DESIGN 3. EXPERIMENTAL DESIGNS ii. SOLOMON FOUR GROUP DESIGN GROUP A R O 1 XO 2 GROUP B R O 1 XO 2 GROUP C RXO 2 GROUP D RXO 2

65 RESEARCH DESIGN 3. POSTTEST ONLY CONTROL GROUP DESIGN: NO PRE-TEST. NEED TO ENSURE THAT GROUPS ARE SIMILAR.

66 RESEARCH DESIGN PROS OF EXPERIMENTAL DESIGNS TEST CAUSE-EFFECT.

67 RESEARCH DESIGN CONS OF EXPERIMENTAL DESIGN NEED TO KNOW WHICH VARIABLES MAY BE IMPORTANT IN PREDICTING OUTCOMES (DEPENDENT VARIABLE). HEALTH SCIENCES OFTEN DON’T; KNOWLEDGE IS AT EARLIER STAGE OF DEVELOPMENT.

68 RESEARCH DESIGN IN HEALTH SCIENCES, SOME INTERVENTIONS DO NOT ETHICALLY LEND THEMSELVES TO RANDOMIZATION. CAN’T FORCED PEOPLE TO PARTICIPATE (RANDOM SELECTION). WHAT WOULD BE EXAMPLES OF THIS?

69 RESEARCH DESIGN NONEQUIVALENT CONTROL GROUP DESIGN (POST-TEST ONLY ) GROUP A X O --------------------------------- GROUP B X 0


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