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Hi, I am planning to externally validate a logistic prediction model in a new cohort. Outcome is mortality. The betacoefficients were derived from a previous published article. It seems not possible in R to assign fixed beta coefficients to predictors like lrm (death ~ intercept+beta1*var1+beta2*var2...). How do i solve this problem? Thank you in advance. Joey L -- View this message in context: http://www.nabble.com/H...

...ake intercept Intercept <- meanyj - meanxj * betacoeff ## Make R the pearson produce moment correlation coefficient if (varYj==0 | varXj==0){ corrCoeff <- 0 }else{ corrCoeff <- (sumXjYj - ((sumXj * sumYj) / n)) / ((sdxij * sdxik)^0.5) } ## Make sample variances of betacoefficient and intercept variancebeta <- (varYj / varXj) * ((1 - (corrCoeff ^ 2)) / n) varianceintercept <- (varYj / n) * (1 - corrCoeff) * (2 + ((meanxj ^ 2) * ((1 + corrCoeff) / varXj))) sdbeta <- variancebeta^0.5 sdintercept <- varianceintercept^0.5 list(betacoeff=betacoeff, # &lt...