Table 2.
Combining Respondents' Attitudes and Self-perceptions about EBM into 4 Factors to Use in Further Analyses (N = 199)
| Attitudes and Self-perceptions about EBM | Factor Analysis* | Mean ±SD | Cronbach's α† |
|---|---|---|---|
| How well you feel you understand | |||
| 1. Sensitivity and specificity | 0.81 | 4.0 ± 1.0 | |
| 2. Prevalence | 0.83 | 4.0 ± 1.0 | |
| 3. Case-control study | 0.85 | 3.7 ± 1.2 | |
| 4. Cohort study | 0.86 | 3.6 ± 1.2 | |
| 5. Meta-analysis | 0.83 | 3.5 ± 1.3 | |
| Factor 1: Understanding of study type, sensitivity, and specificity (mean of 1 to 5 above) | 3.7 ± 0.9 | 0.90 | |
| How well you feel you understand | |||
| 1. Likelihood ratios | 0.82 | 2.8 ± 1.2 | |
| 2. Confidence Intervals | 0.76 | 3.2 ± 1.3 | |
| 3. Relative risk | 0.80 | 3.6 ± 1.1 | |
| 4. Absolute risk reduction | 0.87 | 3.1 ± 1.2 | |
| 5. Odds ratio | 0.90 | 2.8 ± 1.3 | |
| 6. Number needed to treat | 0.76 | 3.2 ± 1.2 | |
| Factor 2: Understanding of statistics used in articles (mean of 1 to 6 above) | 3.1 ± 1.0 | 0.91 | |
| Importance in my daily practice of knowing | |||
| 1. How to search medline to find an article | 0.78 | 3.3 ± 1.3 | |
| 2. How to evaluate the validity of a study | 0.82 | 3.4 ± 1.1 | |
| 3. And using positive/negative likelihood ratios | 0.81 | 3.1 ± 1.2 | |
| 4. And understanding odds ratios of risk factors | 0.70 | 3.2 ± 1.0 | |
| 5. Medication's number needed to treat | 0.80 | 3.1 ± 1.2 | |
| Factor 3: Importance of core EBM skills in daily practice (mean of 1 to 5 above) | 3.2 ± 0.9 | 0.86 | |
| Importance in my daily practice of knowing | |||
| 1. And using the sensitivity and specificity of a test | 0.74 | 3.7 ± 1.0 | |
| 2. And understanding the prevalence of a disease | 0.87 | 3.8 ± 0.9 | |
| 3. And understanding relative risks of treatments | 0.86 | 4.0 ± 0.9 | |
| Factor 4: Importance of epidemiology terms in daily practice (mean of 1 to 3 above) | 3.8 ± 0.8 | 0.80 | |
*
Promax rotation factor loading values for each variable are listed. The values provided by factor analysis help to group variables into factors that approach a similar theme. When the Promax values were similar between 2 factors, the Varimax values were checked for separation.
†
Cronbach's α is a measure of the internal consistency reliability of a measurement instrument. It checks to see if respondents answer a group of questions in the same direction. The addition of any one variable to the group did not decrease the α.