help batplot
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Title
    Produces a Bland-Altman plot when there is a relationship between paired
    differences and their average

Syntax

        batplot varname1 varname2 [if] [in] [, options]

    options               Description
    -------------------------------------------------------------------------
    Main
      info                 specifies that the percentage of points outside
                            the limits of agreement are displayed as a
                            subtitle.
      valabel(varname)     specifies that the points outside the limits of
                            agreement be labelled using the variable varname.
      shading(min max)     specifies the extent of shading beyond the range
                            of the data.
      dp(#)                specifies the precision of the numbers in the
                            title of the graph.
      notrend              specifies that the original Bland-Altman plot
                            (without a trend) be plotted.
      moptions             specifies options for the markers that lie outside
                            the limits of agreement.
      scatter              specifies options for the scatter part of the
                            final plot, see scatter.
      twoway_options       specifies options for example titles and labels.
    -------------------------------------------------------------------------


Description

    batplot produces a Bland-Altman plot adjusted for trend.

    The standard Bland-Altman plot is between the difference of paired
    variables versus the average, this is produced using the notrend option.
    The main addition that this command handles is when there is a linear
    relationship between the the paired difference and the paired average. A
    regression model is used to adjust the limits of agreement accordingly.
    This is particularly useful when the two variables might be measured on
    different scales and hence a straight conversion factor would recalibrate
    the two variables.

Options

        +------+
    ----+ Main +-------------------------------------------------------------

    info specifies that the percentage of points outside the limits of
        agreement are displayed as a subtitle. Additionally when using the
        notrend option the limits of agreement and mean difference are
        included in the subtitle.

    valabel(varname) specifies that the points outside the limits of
        agreement be labelled using the variable varname.

    shading(min max) specifies the extent of shading beyond the range of the
        data. The default is that the limits of shading is determined by the
        values in the xlabel option.

    dp(#) specifies the precision of the numbers in the title of the graph.
        The default is 2 decimal places.

    notrend specifies that the original Bland-Altman plot (without a trend)
        be plotted.

    moptions specifies options for the markers that lie outside the limits of
        agreement, the options can be anything from the scatter marker
        options scatter##marker_options.

    scatter specifies options for the scatter part of the final plot.

Examples

    Using the auto.dta dataset supplied with STATA 8 this command can check
    whether there is agreement between turning circle (ft) and miles per
    gallon, click the highlighted text in order,

    sysuse auto, clear

    batplot mpg turn

    This is the most basic graphic and using twoway options the look can be
    improved by clicking below,

    batplot mpg turn, title(Agreement between mpg and turn) xlab(26(4)38)

    By specifying extra options the outlying points can be labelled and
    identified by the car make,

    batplot mpg turn, title(Agreement between mpg and turn) info
        valabel(make) xlab(26(4)38)

    To obtain the original Bland Altman plot use the notrend option,

    batplot mpg turn, title(Agreement between mpg and turn) info
        valabel(make) notrend xlab(26(4)38)

    To improve the labelling of the point VW it may be preferable to change
    the clock position of the label i.e.  labels could appear to the left of
    the point. This is handled below with moptions().

    batplot mpg turn, title(Agreement between mpg and turn) info
        valabel(make) notrend xlab(26(4)38) moptions(mlabp(9))

    Additionally in the case of multiple scatter points by using the
    scatter() option the user can specify to "jitter" datapoints

    batplot mpg turn, notrend xlab(26(4)38) moptions(mlabp(9)) sc(jitter(4))


Author

Adrian Mander, MRC Biostatistics Unit, Cambridge, UK.

Email adrian.mander@mrc-bsu.cam.ac.uk

Also see

Related commands

HELP FILES
baplot (if installed)