The Stats Method


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The Stats Method

  1. 1. Teaching Medical Students, Interns, and Residents to read Medical Literature: The STATS Method
  2. 2. Session Objectives 1) Examine the current trends in physician use of medical literature. 2) Explain why teaching medical students, interns, and residents how to read medical literature is important. 3) Explore the STATS Method to research evaluation.
  3. 3. Current Trends in Physician use of Medical Literature The Good, the Bad, and the Lack of Probability
  4. 4. The Good
  5. 5. Growth in Clinical Trials According to the Centre for Evidence Based Medicine, there are now around 1 million clinical trials that have been completed.
  6. 6. Trial Classification (NIH Standards) Phase I Trials <ul><li>20-80 Participants </li></ul><ul><li>Examine drug/therapy safety, dosage recommendations, and possible side effects </li></ul>
  7. 7. Phase II Trials <ul><li>100-300 Participants </li></ul><ul><li>Purely a Safety Evaluation </li></ul>Phase III Trials <ul><li>1,000-3,000 Participants </li></ul><ul><li>Confirms effectiveness, monitor’s side effects, compares to other treatments, collects info to allow for safe usage of drugs/treatments </li></ul>
  8. 8. Phase IV Trials <ul><li>Post Marketing Examine </li></ul><ul><li>Collects additional information on risks, benefits and optimal use </li></ul>
  9. 9. Growth in Medical Research In 2002 alone, there were 522,943 articles published in some 4,600 medical journals catalogued by PubMed. There is an abundance of medical research being conducted!
  10. 10. The Bad
  11. 11. Last 5 Years <ul><li>1999 – 473,044 </li></ul><ul><li>2000 – 512,226 </li></ul><ul><li>2001 – 518,741 </li></ul><ul><li>2002 – 522,943 </li></ul><ul><li>2003 – 100,001 </li></ul><ul><ul><li>As of March 24, 2003 </li></ul></ul>
  12. 12. That’s a total of 2,126,955 Articles in just the last 5 years
  13. 13. According to the PubMed Website 1 , they have over 12 million citations dating back to the 1960s. So the last five years accounts for 18% of all of those citations.
  14. 14. To stay up-to-date with the current medical literature, you would have to read about 6,000 research articles a day.
  15. 15. How many minutes did you spend last week reading about your patients? 2 Stage of Career Range of median reading times % who reported NO reading in the last week Medical students 60-120 min 0% House officers 0-20 min up to 75% Senior house officers 10-30 min up to 15% Attendings 10-90 min up to 40% Senior Attendings 10-45 min up to 15% Consultants graduating since 1975 15-60 min up to 30% Consultants graduating pre-1975 10-45 min up to 40%
  16. 16. Medical Knowledge with Years Since Graduation 3
  17. 17. The Probability
  18. 18. Statistics is simply a matter of mathematical probability. Most modern medical research is based in statistics.
  19. 19. It is estimated that nearly 50% of all medical research articles contain serious methodological and/or statistical errors 4 .
  20. 20. Why teaching medical students, interns, and residents about research is so important
  21. 21. Paradigm Shift 5 E B M Evidence Based Medicine
  22. 22. EBM Defined is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. The practice of EBM means integrating individual clinical expertise with the best available external clinical evidence from systematic research.
  23. 23. Traditional vs. EBM Training Sackett et al. (1977) Study on EBM and Hypertension Treatment
  24. 24. EBM in the USA In the early 1990s, JAMA established the Evidence-Based Medicine Working Group 5 . This group, released a series of articles about reading medical literature throughout the 1990s and early 2000s 7 .
  25. 25. The STATS Method
  26. 26. S T A T S Sample Treatment Argument Testing Significance
  27. 27. SAMPLE
  28. 28. Questions to ask about the sample. 1. How were participants selected for inclusion in the study? 2. How were they approached for inclusion? 3. Do study participants have special characteristics?
  29. 29. Questions to ask about the sample. 4. Do the demographics of the study bias the study in any direction? 5. Does the location of the participants bias the study in any direction? 6. What could you do as a researcher to prevent sampling bias?
  30. 30. TREATMENT
  31. 31. Treatment Defined “ Treatment” refers to those variables actively manipulated or measured in a scientific study.
  32. 32. Variables Any entity that can take on different values.
  33. 33. Dependent Variables The variable that is effected or not effected by another variable in a research study.
  34. 34. Independent Variables The variable that is being manipulated or examined in a study to see if it effects the dependent variable.
  35. 35. Ultimately We want Causation IV DV We want the IV to cause a difference in the DV.
  36. 36. FOR EXAMPLE Bioloical Sex Physical Aggression Is there a difference between females and males and their use of physical aggression? The treatment is how we go about measuring and explaining this process.
  37. 37. Questions to ask about the treatment. 1. What is the primary dependent variable studied in the article? 2. How did the researchers go about measuring this variable? 3. Did the researchers attempt to manipulate the target variable? If so, how?
  38. 38. ARGUMENT
  39. 39. Logical argumentation should be the basis for all scientific research.
  40. 40. A logical argument in science is called a hypothesis.
  41. 41. Questions to ask about the arguments. 1. Was the argument for the study made clear in the article? 2. Is the article’s argument supported by current medical research and practice? 3. Is the argument in the article based on science or conjecture?
  42. 42. TESTNG
  43. 43. Testing is the process a researcher goes through to either prove or not prove a hypothesis.
  44. 44. Two Types of Tests 1. Difference Tests 2. Relationship Tests
  45. 45. Difference Tests A difference test attempts to see if there is a difference between the means of two or more groups in relation to one or more dependent variable(s).
  46. 46. FOR EXAMPLE Bioloical Sex Physical Aggression In this case, we wanted to see if there was a difference in the mean scores of female and male physical aggression.
  47. 47. Two Types of Difference Tests <ul><li>Non-Parametric Tests – Involve Nominal and Ordinal Variables </li></ul><ul><li>(x 2 or rank order test) </li></ul>2. Parametric Tests – Involve interval or ratio variables with each other or with nominal and ordinal variables (t-tests or ANOVAs)
  48. 48. Relationship Tests A relationship test attempts to see if two (or more) variables can be plotted in a linear fashion.
  49. 49. Relationships
  50. 50. Two Types of Relationship Tests <ul><li>Symmetric – Unable to designate cause and effect </li></ul><ul><li>(Correlation) </li></ul>2. Asymmetric – Existence of explanatory variables or predictors (Regression)
  51. 51. BIG NOTE Correlation does not mean causation However, Causation does mean Correlation
  52. 52. Significance
  53. 53. What is the actual significance of this study? If research doesn’t say anything new, why should we care?
  54. 54. Activity
  55. 55. Concluding Thoughts 1. EBM is a new direction for medical practitioners. 2. With the abundance of research available we have to be more cynical. 3. As people involved in post-graduate medical education, we need to teach critical analysis of research.
  56. 56. Concluding Thoughts cont… 4. Ask questions about research based on the STATS method. 5. Learn more about how research is actually conducted. Don’t be a sucker!!! 6. One study does not equal science.
  57. 57. Prepared by: Jason S. Wrench, Ed. D. Medical Educational Specialist West Virginia School of Osteopathic Medicine