241109 rm-p.l.-experimental design

1,820 views

Published on

Published in: Health & Medicine, Business
0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
1,820
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
70
Comments
0
Likes
2
Embeds 0
No embeds

No notes for slide

241109 rm-p.l.-experimental design

  1. 1. EXPERIMENTAL DESIGN DR. PREMILA LEE, Professor, Dept of Surgical Nursing & CNE & Research, College of Nursing, Christian Medical College, Vellore
  2. 2. INTRODUCTION <ul><li>Purpose of scientific research is to determine cause & effect relationship </li></ul><ul><li>To determine the efficacy of an intervention </li></ul><ul><li>Researcher – active </li></ul><ul><li>Provides for evidence based practice </li></ul>
  3. 3. Is there an intervention? No Non experimental research yes Is there random assignment to treatment groups? Yes Experimental research Are there measures to compensate for lack of random assignment No No Yes Quasi experimental Pre experimental
  4. 4. TYPES <ul><li>True experimental </li></ul><ul><li>Quasi experimental </li></ul>
  5. 5. CHARACTERISTICS <ul><li>Manipulation </li></ul><ul><li>Control </li></ul><ul><li>Randomization </li></ul>
  6. 6. MANIPULATION <ul><li>Researcher gives intervention or treatment </li></ul><ul><li>Manipulates the independent variables </li></ul><ul><li>Observe the effect </li></ul>
  7. 7. CONTROL <ul><li>Used as a basis of comparison </li></ul><ul><li>Possibilities for the counterfactual </li></ul><ul><li>- Alternative intervention </li></ul><ul><li>- Placebo effect </li></ul><ul><li>- Standard care </li></ul><ul><li>- Wait list control group </li></ul>
  8. 8. RANDOMIZATION <ul><li>Random assignment </li></ul><ul><li>Every subject has an equal chance </li></ul><ul><li>Cluster randomization </li></ul><ul><li>Advantages </li></ul><ul><li>- No systematic bias </li></ul><ul><li>- Allows comparison </li></ul><ul><li>- Increases confidence </li></ul>
  9. 9. EXPERIMENTAL DESIGN <ul><li>Pre test - Post test control group design </li></ul><ul><li>Solomon four group design </li></ul><ul><li>Factorial design </li></ul><ul><li>Randomized block </li></ul><ul><li>Cross over design </li></ul>
  10. 10. PRETEST POSTTEST DESIGN R E C Pre test X Post test Pre test Post test
  11. 11. SOLOMON FOUR GROUP DESIGN R E2 Pre test X Post test X Post test C1 Pre test Post test E1 C2 Post test
  12. 12. FACTORIAL DESIGN Type of stimulation Daily exposure Auditory A1 Tactile A2 15 minutes B1 A1 B1 A2 B2 30 minutes B2 A1 B2 A2 B2 45 minutes B3 A1 B3 A2 B3
  13. 13. RANDOMIZED BLOCK DESIGN <ul><li>Similar to factorial design in structure </li></ul><ul><li>Two independent variable (factor) - one is not manipulated – known as blocking variable </li></ul><ul><li>Can include more than one blocking variable </li></ul>
  14. 14. CROSS OVER DESIGN <ul><li>Repeated measures design </li></ul><ul><li>Within subject design </li></ul><ul><li>Subjects as their own control </li></ul><ul><li>Equivalence among subjects </li></ul>
  15. 15. STRENGTHS <ul><li>Powerful to test hypothesis </li></ul><ul><li>Yields highest quality of evidence </li></ul><ul><li>Provides greater confidence </li></ul>
  16. 16. LIMITATIONS <ul><li>Impractical or impossible at all times </li></ul><ul><li>Artificiality </li></ul><ul><li>Difficulty in clinical setting </li></ul><ul><li>Hawthorne effect </li></ul><ul><li>Ethical concern </li></ul><ul><li>Costly </li></ul>
  17. 17. QUASI EXPERIMENTAL <ul><li>Non equivalent control group before and after design </li></ul><ul><li>Time series design </li></ul>
  18. 18. NON EQUIVALENT CONTROL GROUP BEFORE AND AFTER DESIGN O1 X O2 O1 O2 E C
  19. 19. LIMITATIONS <ul><li>Lack of randomization </li></ul><ul><li>Control group is not equivalent </li></ul>
  20. 20. TIME SERIES DESIGN O1 O3 O2 O4 X O5 O6 O7 O8
  21. 21. Time series non equivalent control group design O1 O3 O2 O4 X O5 O6 O7 O8 O1 O3 O2 O4 O5 O6 O7 O8
  22. 22. PRE EXPERIMENTAL <ul><li>One group pre test post test design </li></ul><ul><li>One group posttest- only design </li></ul><ul><li>Non equivalent control group after only design </li></ul>
  23. 23. One group pretest post test design O1 X O2
  24. 24. ONE GROUP POSTTEST ONLY DESIGN X O2
  25. 25. POSTTEST ONLY DESIGN WITH COMPARISON GROUP R E Non equivalent comparison group X Post test Post test
  26. 26. QUASI EXPERIMENTAL - STRENGTHS <ul><li>Practical & feasible </li></ul><ul><li>Adaptable to real world </li></ul><ul><li>Some studies it is the only way </li></ul>
  27. 27. QUASI EXPERIMENTAL - STRENGTHS <ul><li>Cause & effect influences less convincing </li></ul><ul><li>Not objective </li></ul><ul><li>Experiment & comparison groups are not equal </li></ul>
  28. 28. CONCLUSION <ul><li>To meet the growing demand for evidence based practice </li></ul>

×