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From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: error bars |

Date |
Thu, 19 Jun 2008 18:07:56 +0100 |

Several issues have been raised in this thread, principally what is best to do and how to do it. I dislike "detonator plots" (Paul Seed's name?), a.k.a. "dynamite plots" (Frank Harrell's name?), as heartily as anyone else, but let that pass. Moleps here asserts that -ciplot- (one of my programs on SSC) produces two identical error bars for two different variables. I can't see Moleps' data from here but I believe that assertion to be false, unless of course the variables happen to collapse to the same confidence intervals. sysuse auto ciplot turn mpg, by(foreign) is one simple example to the contrary. In another posting, Moleps makes the same assertion about -cibplot- (also mine on SSC), and the same rebuttal applies. -cibplot- was written a while back in 2003 in response to a similar thread. It was a quick hack. -cibplot- incorporates a prejudice of mine in that error bars are drawn on top of estimate bars and so cannot be overwritten, except by devious means. However, it has taken me five years to realise that -cibplot- was unnecessary all along. The -recast()- option applied to -ciplot- produces estimate bars rather than estimate point symbols. ciplot turn mpg , by(foreign) recast(bar) The usual rhetoric here is start bars at 0 so that error bars look trivially small: ciplot turn mpg , by(foreign) recast(bar) yla(0(10)40) As old hands will realise, this is not a matter of -ciplot- being especially smart. Rather, if I see far, I am standing on StataCorp's, specifically Vince Wiggins' shoulders. (He'd rather I dismounted promptly.) But -ciplot- will get no further development from me. My affections have transferred to -stripplot- (also on SSC), which shows the raw data too. Nick n.j.cox@durham.ac.uk moleps islon I' making a double error bar graph- e.g two different variables x and y with error bars categorised according to z. I've tried using ciplot x y, by(z) however I get a graph with two identical error bars (though different symbol, but identical values) for each instance of z. Any idea how to remedy this? If I need to make bars (a bar graph) for each category and then have the positive part of the error bar projecting from the top- how do I go about this? On Mon, Jun 16, 2008 at 2:23 PM, Nick Cox <n.j.cox@durham.ac.uk> wrote: > Standard errors can come from lots of places, including the -ci- > command. > > Moleps seems to be implying that -ci- does the right calculation for his > or her purposes. > > (I note that Moleps has yearly results, but -ci- for separate years does > nothing about any time series structure in the data, for example about > taking serial correlation into account.) > > -ciplot- and -stripplot- from SSC both do -ci-type calculations and > graphing in one. moleps islon <moleps2@gmail.com> wrote: >> I need to make a an error-bar graph categorised by year. I've tried >> using serrbar mean(x) etc, but I cant find a command for the standard >> error. Do I need to run a CI, generate a new variable from the ci >> result and feed that into serrbar? > * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**st: error bars***From:*"moleps islon" <moleps2@gmail.com>

**Re: st: error bars***From:*Maarten buis <maartenbuis@yahoo.co.uk>

**RE: st: error bars***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**Re: st: error bars***From:*"moleps islon" <moleps2@gmail.com>

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