Table 3. Summary of statistical methods.
| 2002–2006 | 2007–2011 | ||||
| Statistical methods | No. of publications (N = 91) | (%) | No. of publications (N = 98) | (%) | p-value |
| Descriptive statistics | 88 | 97 | 94 | 96 | 0.78 |
| Inferential methods | |||||
| t-test | 13 | 14 | 19 | 19 | 0.35 |
| Contingency table analysis | |||||
| Basic (chi-square/Fisher exact) | 25 | 27 | 37 | 38 | 0.13 |
| Correlation | 9 | 10 | 1 | 1 | - |
| Epidemiologic statistics | 39 | 43 | 45 | 46 | 0.67 |
| Analysis of variance | 3 | 3 | 1 | 1 | - |
| Regression | |||||
| #Multiple regression | 13 | 14 | 31 | 32 | 0.005 |
| Survival analysis | |||||
| Kaplan-Meier | 69 | 76 | 53 | 54 | 0.002 |
| Cox-Regression | 68 | 75 | 63 | 64 | 0.12 |
| Time dependent Cox regression | 21 | 23 | 11 | 11 | 0.03 |
| Cox-Regression with frailty | 1 | 1 | 6 | 6 | - |
| Non-parametric methods | 86 | 95 | 91 | 93 | 0.64 |
| No. of different inferential methods | |||||
| 2 or 3 methods | 10 | 11 | 11 | 11 | 0.96 |
| 4 or 5 methods | 44 | 48 | 43 | 44 | 0.54 |
| More than 5 methods | 37 | 41 | 44 | 45 | 0.56 |
| ¶Basic analysis | 36 | 40 | 45 | 46 | 0.38 |
| *Advanced analysis | 90 | 99 | 97 | 99 | 0.96 |
#
Refers to logistic, conditional logistic, generalized estimating equations and Poisson regression methods.
¶
Refers to Student t-test, Chi-Square and Fishers Exact test, Mann-Whitney, Kruskall-Wallis, Wilcoxon, simple ANOVA and correlation.
*
Refers to Logistic Regression, Conditional Logistic Regression, Poisson Regression and Survival Analysis and Epidemiologic statistics.