. help twoway pcarrow
Dopey example:
sysuse auto
gen mpg2 = mpg + 2
gen weight2 = weight - 100
twoway pcarrow mpg weight mpg2 weight2
In other words, you must construct x and y variables specifying the
start of each arrow and similarly specifying the end of each arrow.
See also
SJ-5-2 gr0015 . . . . . . . . Stata tip 21: The arrows of outrageous
fortune
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N.
J. Cox
Q2/05 SJ 5(2):282--284 (no
commands)
tip for using graph twoway pcarrow for graphing changes
over time
That Tip is accessible to all under the three-year window.
Nick
n.j.cox@durham.ac.uk
Stephen P. Jenkins
A colleague wishes to summarise her estimates from a latent growth
curve model. I seek tips about how to construct graphs in the format
often used in this context.
In the graphs, the horizontal axis shows age. The vertical axis shows
the predicted n-year trajectory for a latent outcome. Plotted for each
of several starting ages is a vector or arrow -- a straight line
summarising the estimated trajectory going from the start year t to
the end year t+n with an arrowhead at the latter end. So, the graph is
the collection of vectors, and the vectors looked at collectively
themselves indicate a lifecourse trajectory (since number of years
used in each vector is relatively small, and 5-10 vectors may be used
to cover the whole life course).
An example is shown as "Figure 1: Predicted 8-year aging vectors of
physical impairment by educational attainment and family income", in
Jinyoung Kima and Emily Durden, "Socioeconomic status and age
trajectories of health", Social Science & Medicine 65 (2007) 2489-2502
http://www.ncbi.nlm.nih.gov/pubmed/17765375
The substantive medical application is not the essence of my question.
My questions concerns how to draw graphs like this, and related issues
such as data set-up. -graph twoway pccapsym- discussed on [G] p. 259,
and -graph twoway pcspike-, [G] p.268, seem to offer related
facilities but not quite what is requested here.
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