Tools for Epidemiology cctable.ado, for Stata version 8.0 or higher Sept 2007
Univariate case control analysis for each exposure, results are summarized into one table. One row, one exposure. Result file contains: ordering number of exposure(id), name of variable (exposure), total number of cases, number of exposed cases, percentage of exposed among cases, number of controls, number of exposed controls, percentage of exposed among controls, odds ratio, 95%CI interval, 95% p-value.
Collaborative work by Gilles Desve and Peter Makary. Special thanks to Alain Moren. In case of any question please contact us: g.desve@epiconcept.fr peter.makary@ktl.fi (Opinions, notices are welcome as well!)
Summary table for case-control study
Syntax
cctable [varlist] [if] [in] [, options]
options Description ------------------------------------------------------------------------- Main exact Calculate 2-sided exact p-value (default is chi square test p-value) nosort Results are displayed in the same order of variables in the command line or Sort result by odds ratio, descending order pe Sort result by percentage of exposed among cases, descending order pvalue Sort result by pvalues, ascending order (default) replace Replace the current dataset with the cctable result noabbreviate Display full exposure name (default fisrt 12 chars) ------------------------------------------------------------------------- by may not be used with cctable.
Description
cctable calculate number and percentage of exposed among cases and controls, odds ratio, 95%CI interval, 95% p-value for each variable of varlist. The result table could be sorted by odds ratio, p-value or percentage of exposed.
Result could be copied with "copy table" in order to be pasted in Excel. Alternatively, the replace option store results as a new dataset. Then, results can be exported or saved in a new dataset.
Options
+------+ ----+ Main +-------------------------------------------------------------
exact requests Fisher's exact p be calculated rather than the chi-squared and its significance level. Specifying exact is recommended whenever samples are small. A conservative rule of thumb for 2x2 tables is to specify exact when the least-frequent cell contains fewer than 1,000 cases. When the least-frequent cell contains 1,000 cases or more, there will be no appreciable difference between the exact significance level and the significance level based on the chi-squared, but the exact significance level will take considerably longer to calculate. Note that exact does not affect whether exact confidence intervals are calculated.
nosort Specifies that the order of the exposures will be the same in the result table as it was in the command.
or Results will be sorted by odds ratio in descending order.
pe Results will be sorted by percentage of exposed among cases in descending order.
pvalue Results will be sorted by p-value in ascending order. If no other sorting option is used, results will be sorted by ascending p-value as default.
replace Specifies that the result table will replace the original dataset in the memory and it will appear in the browser window. It means that the original dataset will be deleted from the memory. preserve then restore may be used to get back the original dataset, or upload it again with the use command. replace is used to create dataset from the result table (e.g. to save it), or to solve "copy table" incompatibilities in certain cases.
noabbreviate Displays full exposure name (default 12 first chars).
Remarks As with the cc command, variables used with cctable must be coded as 0/1. Sorting results only available in version 9 For detailed information contact g.desve@epiconcept.fr or peter.makary@ktl.fi
Examples
. cctable ill mousse tiramisu beer sex agegrp The result table is sorted by ascending p-value
. cctable ill mousse tiramisu beer, or The result table is sorted by descending odds ratio
Also see cstable, csinter, cc.
Manual:
Online: