;;config_different_parameterizations_different_covariates.scm ;;lines starting with ; are comments ;;there is no file run34.mod in the extra material, this example config file is for a hypothetical model file model=run34.mod directory=scm_run34 search_direction=forward p_forward=0.05 continuous_covariates=WGT,APGR categorical_covariates=SEX logit=BIO ;;scm was not originally designed to allow different parameterizations for different ;;covariates, but this is possible to work around. ;;The general strategy is as follows: ;;In [valid_states] set the list for continuous and categorical to suit the parameter-covariate pair ;;with *the largest number* of parameterizations you want to test. Always start with 1 for not included. ;;State 1 must never be redefined. ;;Then go through each parameter-covariate pair. If the number of parameterizations equals the ;;number in [valid_states], only change the meaning of the state digits if necessary, ;;like below where the meaning of state 5 for V:WGT is changed to exponential. ;;If the number of parameterizations is smaller than in [valid_states], set ;;the N superfluous leading states, after the initial state 1, in [valid_states] to 'none', ;;as below where there is one state ;;too many for BIO so therefore the second state is changed to none. The remaining states ;;are redefined as desired, like below where state 5 is redefined to linear for all covariates ;;on BIO. ;;If a number of leading states have been set to none, set [included_relations] to the last ;;of the states that is 'none', as below where included_states is BIO=APGR-2,WGT-2 ;;The example above only uses the pre-defined parameterizations, but it is of course ;;possible to define and use new parameterizations. ;;An example: ;;Let's assume that we want the following ;; Start at To be tested ;; BIO-WGT none linear (since BIO is a logit we only want to test linear inclusion) ;; BIO-APGR none linear (since BIO is a logit we only want to test linear inclusion) ;; V-APGR none linear and then power if linear is found significant ;; V-WGT none linear and then exponential if linear is found significant ;; V-SEX none linear ;;Below is how to achieve this [test_relations] BIO=WGT,APGR V=WGT,APGR,SEX ;;The first valid state must always be 1 [valid_states] continuous = 1,2,5 categorical = 1,2 [code] ;;Never redefine state 1 ;;only linearly included covariates should be considered for logit ;;transformed parameters, not any other function form. ;;We redefine state 2 to be 'none/not included' for any covariate on BIO, and ;;state 5 to be linear. ;;We redefined state 5 to be exponential instead of the default power for V-WGT BIO:*-2=none BIO:*-5=linear V:WGT-5=exponential ;;Setting included_relations forces inclusion of some relations. ;;These relations should never be manually added to ;;the input model, scm will add them. ;;[included_relations] is required when search_direction=backward, ;;otherwise there are no relations to remove ;;Since in this example we have redefined state 2 to 'none' ;;for BIO-APGR and BIO-WGT it is essential to set included_relations ;;to 2. Otherwise scm would test and compute p-value for changing the state ;;from 1 to 2, i.e. from 'none' to 'none', which will of course never give ;;a significant improvement of the model fit. [included_relations] BIO=APGR-2,WGT-2