/* PubH 7450 Exampel 13.1b: fitting a PHM with correlated survival data. */ options ls=80 center pagesize=60 number label; goptions device = PS; /* graphs are saved in a file names sasgraph.ps */ data larynx; infile '/home/merganser/weip/public_html/course/7450/data/rats.txt' firstobs=18; input time status trt litter; proc phreg; model time*status(0) = trt ; title 'Standard PHM (for independent data)'; proc phreg covs(aggregate); model time*status(0) = trt ; id litter; title 'Marginal PHM'; proc phreg; model time*status(0) = trt ; strata litter; title 'Stratified PHM'; Standard PHM (for independent data) 1 Summary of the Number of Event and Censored Values Percent Total Event Censored Censored 150 40 110 73.33 Model Fit Statistics Without With Criterion Covariates Covariates -2 LOG L 371.631 363.775 AIC 371.631 365.775 SBC 371.631 367.464 Testing Global Null Hypothesis: BETA=0 Test Chi-Square DF Pr > ChiSq Likelihood Ratio 7.8559 1 0.0051 Score 8.5388 1 0.0035 Wald 7.9949 1 0.0047 Analysis of Maximum Likelihood Estimates Parameter Standard Hazard Variable DF Estimate Error Chi-Square Pr > ChiSq Ratio trt 1 0.89747 0.31741 7.9949 0.0047 2.453 ************************** Marginal PHM 2 Criterion Covariates Covariates -2 LOG L 371.631 363.775 AIC 371.631 365.775 SBC 371.631 367.464 Testing Global Null Hypothesis: BETA=0 Test Chi-Square DF Pr > ChiSq Likelihood Ratio 7.8559 1 0.0051 Score 8.5388 1 0.0035 Modified Score 7.6473 1 0.0057 Wald 8.9318 1 0.0028 Analysis of Maximum Likelihood Estimates Parameter Standard StdErr Hazard Variable DF Estimate Error Ratio Chi-Square Pr > ChiSq Ratio trt 1 0.89747 0.30030 0.946 8.9318 0.0028 2.453 *************************** Stratified PHM 3 Summary of the Number of Event and Censored Values Percent Stratum litter Total Event Censored Censored 1 1 3 1 2 66.67 2 2 3 0 3 100.00 3 3 3 0 3 100.00 4 4 3 0 3 100.00 5 5 3 0 3 100.00 6 6 3 2 1 33.33 7 7 3 2 1 33.33 8 8 3 1 2 66.67 9 9 3 0 3 100.00 10 10 3 1 2 66.67 11 11 3 1 2 66.67 12 12 3 0 3 100.00 13 13 3 2 1 33.33 14 14 3 1 2 66.67 15 15 3 0 3 100.00 16 16 3 0 3 100.00 17 17 3 0 3 100.00 18 18 3 0 3 100.00 19 19 3 0 3 100.00 20 20 3 2 1 33.33 21 21 3 0 3 100.00 22 22 3 0 3 100.00 23 23 3 1 2 66.67 24 24 3 0 3 100.00 25 25 3 0 3 100.00 26 26 3 0 3 100.00 27 27 3 0 3 100.00 28 28 3 2 1 33.33 29 29 3 2 1 33.33 30 30 3 2 1 33.33 31 31 3 0 3 100.00 32 32 3 3 0 0.00 33 33 3 1 2 66.67 34 34 3 1 2 66.67 35 35 3 1 2 66.67 36 36 3 1 2 66.67 37 37 3 0 3 100.00 38 38 3 1 2 66.67 39 39 3 2 1 33.33 40 40 3 2 1 33.33 41 41 3 1 2 66.67 42 42 3 2 1 33.33 43 43 3 2 1 33.33 44 44 3 0 3 100.00 45 45 3 0 3 100.00 46 46 3 0 3 100.00 47 47 3 1 2 66.67 48 48 3 0 3 100.00 49 49 3 1 2 66.67 50 50 3 1 2 66.67 ------------------------------------------------------------------- Total 150 40 110 73.33 Model Fit Statistics Without With Criterion Covariates Covariates -2 LOG L 64.739 59.154 AIC 64.739 61.154 SBC 64.739 62.843 Testing Global Null Hypothesis: BETA=0 Test Chi-Square DF Pr > ChiSq Likelihood Ratio 5.5848 1 0.0181 Score 5.7760 1 0.0162 Wald 5.4424 1 0.0197 Analysis of Maximum Likelihood Estimates Parameter Standard Hazard Variable DF Estimate Error Chi-Square Pr > ChiSq Ratio trt 1 0.87993 0.37719 5.4424 0.0197 2.411