help for srr
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Title

    srr -- Survival Risk Ratio and Independent Survival Risk Ratio Table


Version

    Version 3.0.

    ICDPIC Version 3.0 requires STATA 8.0 or higher.  ICDPIC Version 3.0 has
    been tested in STATA 10 and STATA 11, but the authors believe it should
    also work without incident in STATA 8 and STATA 9.  If you have any
    problems using ICDPIC Version 3.0 in STATA 8 or STATA 9, please inform
    the authors.

    ICDPIC Version 3.0 may be installed from within STATA using the ssc
    command.  If you installed a previous version of ICDPIC from the SSC
    archives website using the ssc command, we suggest that you first delete
    it by typing ssc uninstall icdpic followed by ssc install icdpic.
    Alternatively, you may use ssc install icdpic, replace.  See help for 
    ssc.

    If you installed any previous ICDPIC files obtained directly from the
    authors, please delete them ALL (.ado, .hlp and .dta files) to avoid any
    conflicts with ICDPIC 3.0 files.

    Please enter complete variable names in the ICDPIC Version 3.0 dialog
    boxes.  Do not use abbreviations.

    New to Version 3.0 is the addition of a dialog box (.dlg) file associated
    with each individual ICDPIC Version 3.0 program (.ado) file.  To access
    the ICDPIC dialog box, and all the ICDPIC programs, type: db icdpic.
    Typing icdpic, as in earlier versions, will still work, but ONLY with
    icdpic.  For example, to access the SRR\SRRi Table program directly,
    type: db srr.  Typing srr, as in previous versions, will produce an
    error.

    Fixed in ICDPIC Version 3.0 is the ability to use path\file names
    containing spaces.

    Fixed in ICDPIC Version 3.0 is the ability to run in STATA 11.0.

    Fixed in ICDPIC Version 3.0 is a bug that caused the triss program to
    crash if the rts variable was named anything other than "rts".

    New in ICDPIC Version 3.0 (trauma program only) is the ability to choose
    whether an AIS value of 6 automatically forces an ISS of 75 or to
    automatically have all AIS values of 6 changed to an AIS value of 5 and
    then have the ISS calculated normally.

    All dialog boxes in ICDPIC Version 3.0 have memory.  Each time a dialog
    box is opened within the same STATA session, it will remember the values
    last entered.

    All dialog boxes in ICDPIC Version 3.0 have the following buttons:

      OK executes the program and removes the dialog box from the screen.

      SUBMIT executes the program and leaves the dialog box on the screen.
             Note that if an error message is generated the dialog box may be
             minimized.

      CANCEL removes the dialog box from the screen and does nothing.
             Clicking on the close icon of the dialog box does the same
             thing.

      HELP leaves the dialog box on the screen and presents the program help
           file.  The HELP button has a question mark on it.

      COPY leaves the dialog box on the screen and copies the program command
           to the clipboard.

      RESET resets the values of the controls in the dialog box to their
            initial state, just as if the dialog box were invoked for the
            first time.  Each time a user invokes a dialog box, its controls
            will be filled in with the values the user last entered.  RESET
            restores the control values to their defaults.  The RESET button
            has an R on it.


Syntax

        db srr

    The SRR\SRRi Table dialog box will open.  Follow the instructions.

                                      OR

        db icdpic

    The ICDPIC dialog box will open.  Choose SRR\SRRi Table and click OK or
    Submit.  The SRR\SRRi Table dialog box will open.  Follow the
    instructions.


Description

    srr calculates the survival risk ratio (SRR) and the independent survival
    risk ratio (SRRi) for all valid ICD-9-CM injury codes (N-Codes) in a data
    set and stores them in a file on disk.

    SRR and SRRi are defined by analysis of whatever population is deemed the
    index population.

    SRR is equivalent to the number of survivors with a given N-Code divided
    by the number of survivors plus non survivors with that same N-Code.

    SRRi is equivalent to the number of survivors with a given N-Code (and no
    other N-Codes) divided by the number of survivors plus non survivors with
    that same N-Code (and no other N-Codes).


Options

    ICD-9-CM diagnosis codes in the user's data may, or may not, contain a
    decimal point.  Simply choose the option that applies to your data in the
    SRR\SRRi Table dialog box.


Remarks

    The user's data must contain ICD-9-CM diagnosis codes.  Diagnosis codes
    in the user's data must be of type string.  A decimal point in the
    diagnosis codes is optional.  Diagnosis codes should have a width of 5 (6
    if a decimal point is present).  The diagnosis code prefix must be the
    same for all diagnosis codes and numbered sequentially starting with 1,
    for example, dx1...dxN.

    The user's data also requires a Boolean variable of type byte to indicate
    discharge status.  0 if the patient was discharged alive and 1 if the
    patient died.

    srr adds the following variables to a new file stored on disk:


        dx: N-Code
        survive1: number of observations in the user's data in which a given
            N-Code occurred and the patient survived
        expire1: number of observations in the user's data in which a given
            N-Code occurred and the patient died
        srr: survival risk ratio (SRR), or survive1/(survive1 + expire1)
        survive2: number of observations in the user's data in which a given
            N-Code is the only N-Code and the patient survived
        expire2: number of observations in the user's data in which a given
            N-Code is the only N-Code code and the patient died
        srri: independent survival risk ratio (SRRi), or survive2/(survive2 +
            expire2)


    SRR and SRRi are rounded to the nearest 0.0001.  If SRR or SRRi are
    equal, or round to, 0.0000 or 1.0000 they are replaced with 0.0001 and
    0.9999 respectively.

    srr requires the use of lookup tables ntab_s1.dta and ntab_s2.dta.  These
    data tables are supplied.  _s1 tables are for use with data without the
    decimal point in ICD-9-CM codes and _s2 tables are for data that include
    the decimal point.  See help for icdpic, specifically the LOOKUP TABLES
    part of the Remarks section.


Examples

None


Authors

    David E. Clark, M.D.

        Maine Medical Center, Portland, Maine, USA
        University of Vermont College of Medicine, Burlington, Vermont, USA
        Harvard Injury Control Research Center, Harvard School of Public
            Health, Boston, Massachusetts, USA

        Correspondence to Dr. Clark,
        887 Congress Street, Portland ME 04102
        Email:  clarkd@mmc.org

    Turner M. Osler, M.D.

        University of Vermont College of Medicine, Burlington, Vermont, USA

    David R. Hahn

        Maine Medical Center, Portland, Maine, USA


References

    None


Also see

    help for iciss

    help for icdpic

    help for srr