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help for ^tabrate^                                              (STB-27: ssa7)
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Tabulation of rates by a categorical exposure variable
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    ^tabrate^ fail [xvar] [^if^ exp] [^in^ range] ^e^xposure^(^varname^)^
        [^g^raph ^l^evel^(^#^)^ ^per(^#^)^ ^smr^ ^t^rend]


Description
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^tabrate^ tabulates the rate, formed from the number of failures divided by
the person-years, by different levels of a categorical explanatory variable,
^xvar^. Confidence intervals for the rate are also given.  The variable
^fail^ contains the number of failures, which will be 0 or 1 for individual
records.


Options
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^exposure(^varname^)^ specifies the variable which supplies the denominator of the
    rate or SMR, namely the person-years or expected numbers.

^graph^ requests a graph of rate against ^xvar^; graph options are allowed.

^level(^#^)^ gives the level for the confidence intervals (default 95).

^per(^#^)^ requests the rate to be given as per whatever person-years. The
    default is per 1000 person-years.

^smr^ changes the labeling of the output to that appropriate for SMRs. The
    ^exposure()^ variable must contain the expected number of failures.

^trend^ performs a chi-squared test for trend.


Examples
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 . ^tabrate d loweng, e(y) ^  -- Individual records
 . ^tabrate D loweng, e(Y) ^  -- Poisson frequency records
 . ^tabrate D loweng, e(E) ^  -- Observed and expected


Authors
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        David Clayton, MRC Biostatistical Research Unit, Cambridge
        david.clayton@@mrc-bsu.cam.ac.uk
        Michael Hills, London School of Hygiene and Tropical Medicine, London
        mhills@@lshtm.ac.uk


Also see
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    STB:  STB-27 ssa7
On-line:  help for @lexis@ and @mhrate@