spagplot.hlp.htm

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help for spagplot
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Spaghetti Plot

        spagplot yvar xvar [if exp] [in range], id(idvar) [nofit] [noover]
              [graph options]

    where yvar xvar are the Y and X variables you wish to plot and idvar is
    the variable that identifies a single observation.

NOTE! Spagplot makes the assumption that the first X variable for subject i+1 
is greater than the last X variable for subject "i" and this is not always true. 
When this is false, the lines for two subjects will get connected.

Description

    spagplot allows you to "spaghetti plot", i.e. a plot of an X variable and
    the predicted values for the Y variable forming a regression line of the
    predicted values of Y by X.  A separate regression line is plotted for
    each observation indicated by the idvar variable.

If you specify the nofit option, the actual y values (not the fitted y values
will be plotted.

If you specify the noover option, the overall regression line between
y and x will be suppressed.

Examples

    We will show a number of examples from a data file which contains alcohol
    use alcuse at 3 ages, age 14, 15, and 16 for a number of children
    (identified by the variable id.  The age variable has been centered
    around age 14 and is named {id:age_14}. We first show how to obtain the
    data file.

. use https://stats.idre.ucla.edu/stat/stata/examples/alda/data/alcohol1_pp

    This example shows a basic spaghetti plot of alcohol use by age, broken
    down by id.

. spagplot alcuse age_14 , id( id )

    This example just performs the plot for the first 30 observations.

. spagplot alcuse age_14 in 1/30, id( id )

    This example shows the plot just for the ids below 9.

. spagplot alcuse age_14 if id <= 9, id( id )

    This example adds a title as a graph option.

. spagplot alcuse age_14 , id( id ) ytitle("Predicted Alcohol Use")

    This example adds a title as a graph option, and changes the scheme to
    sj.

. spagplot alcuse age_14 , id( id ) ytitle("Predicted Alcohol Use") scheme(sj)

    This example also changes the note from the default note.

. spagplot alcuse age_14 , id( id ) ytitle("Predicted Alcohol Use") scheme(sj) 
> note("My custom note")

    This example removes the note from the graph entirely.

. spagplot alcuse age_14 , id( id ) ytitle("Predicted Alcohol Use") scheme(sj) 
> note("")



Author

     Statistical Consulting Group
     Institute for Digital Research and Education, UCLA
     idrestat@ucla.edu 

Also see

    Manual:  [R] graph

    Online:  help for graph