I'm trying to create a bar chart in which the frequency is outside the bar and the percentage inside, is it possible? Would post a picture but the system doesn't allow for it yet.
As others pointed out, this is a poor question without code.
It is possible to guess that you are using graph bar. That makes you choose at most one kind and position of bar labels. Much more is possible with twoway bar so long as you do a little work.
sysuse auto, clear
contract rep78 if rep78 < .
su _freq
gen _pc = 100 * _freq / r(sum)
gen s_pc = string(_pc, "%2.1f") + "%"
gen one = 1
twoway bar _freq rep78, barw(0.9) xla(1/5, notick) bfcolor(none) ///
|| scatter one _freq rep78, ms(none ..) mla(s_pc _freq) mlabcolor(black ..) ///
mlabpos(0 12) scheme(s1color) ysc(r(0 32)) yla(, ang(h)) legend(off)
In short:
contract collapses to a dataset of frequencies.
Calculation of percents is trivial, but you need a formatted version in a string variable if the labels are not to look silly. Precise format is at choice.
The frequency scale on the axis is arguably redundant given the bar labels, and could be omitted.
The example puts labels within the bar just above its base at the level of frequency equal to 1. That's a choice for this example and would be too close to the axis if the typical frequencies were much higher.
Related
I am estimating a model in Stata 16 over several subsamples. I want a chart comparing two coefficients of interest over the different subsamples, with axis labels showing which subsample it comes from.
Is there a way to combine both of these on the same panel, with the mileage estimates in one colour and the trunk space in another?
The closest I can get using coefplot is a tiled plot with a set of coefficients of one variable in one panel, and the coefficients for the other variable in another panel (see toy example below). Any idea how to get both on the same panel?
webuse auto
forval v=2/5 {
reg price trunk mpg if rep78==`v'
est store reg_`v'
}
coefplot reg_2 || reg_3 || reg_4 || reg_5, keep(trunk mpg) bycoefs vertical
There's likely a more elegant way to do this with coefplot, but until someone posts that solution: you can use matrices to brute force coefplot into behaving the way you'd like. Specifically, define as many matrices as you have unique covariates, with each matrix's dimension being #specs x 3. Each row will contain the covariate's estimated coefficient, lower CI, and upper CI for a particular model specification.
This works because coefplot assigns the same color to all quantities associated with plot (as defined by coefplot's help file). plot is usually a stored model from estimates store, but by using the matrix trick, we've shifted plot to be equivalent to a specific covariate, giving us the same color for a covariate across all the model specifications. coefplot then looks to the matrix's rows to find its "categorical" information for the labeled axis. In this case, our matrix's rows correspond to a stored model, giving us the specification for our axis labels.
// (With macros for the specification names + # of coefficient
// matrices, for generalizability)
clear *
webuse auto
// Declare model's covariates
local covariates trunk mpg
// Estimate the various model specifs
local specNm = "" // holder for gph axis labels
forval v=2/5 {
// Estimate the model
reg price `covariates' if rep78==`v'
// Store specification's name, for gph axis labels
local specNm = "`specNm' reg_`v'"
// For each covariate, pull its coefficient + CIs for this model, then
// append that row vector to a new matrix containing that covariate's
// b + CIs across all specifications
matrix temp = r(table)
foreach x of local covariates{
matrix `x' = nullmat(`x') \ (temp["b","`x'"], temp["ll","`x'"], temp["ul","`x'"])
}
}
// Store the list of 'new' covariate matrices, along w/the
// column within this matrix containing the coefficients
global coefGphList = ""
foreach x of local covariates{
matrix rownames `x' = `specNm'
global coefGphList = "$coefGphList matrix(`x'[,1])"
}
// Plot
coefplot $coefGphList, ci((2 3)) vertical
I want to make an scatter plot in Stata with points colored according to a categorical variable.
The only way I've found to do this, is to code colors in layers of a twoway plot.
However, this seems a rather convoluted solution for such a simple operation:
twoway (scatter latitud longitud if nougrups4 ==1, mcolor(black)) ///
(scatter latitud longitud if nougrups4 ==2, mcolor(blue)) ///
(scatter latitud longitud if nougrups4 ==3, mcolor(red)) ///
(scatter latitud longitud if nougrups4 ==4, mcolor(green))
Is there a simpler and automatic way to do this?
In this case, the categorical variable nougrups4 came from a cluster analysis. A general solution would be fine, but also a specific solution to draw clusters.
This is how I would do this by hand:
sysuse auto, clear
separate price, by(rep78)
tw scatter price? mpg
drop price?
Or in one line using Nick Cox's sepscatter command from SSC:
sepscatter price mpg, separate(rep78)
The latter command can also output other type of plots with the recast() option.
There isn't a 'simpler' built-in solution for what you want to do.
However, here's a simple wrapper command, which you can extend to meet your needs:
capture program drop foo
program define foo
syntax varlist(min=1 max=3)
quietly {
tokenize `varlist'
levelsof `3', local(foolevels)
local i = 0
local foocolors red green blue
foreach x of local foolevels {
local ++i
local extra `extra' || scatter `1' `2' if `3' == `x', mcolor("`: word `i' of `foocolors''")
}
twoway `extra'
}
end
And a toy example:
clear
set obs 10
generate A = runiform()
generate B = runiform()
generate C = .
replace C = 1 in 1/3
replace C = 2 in 4/7
replace C = 3 in 8/10
foo A B C
I can't quite grasp how to insert a variable's value labels for titles to a graph.
For example, in sysuse auto, the variable foreign takes the value of 0 or 1 where 0 is labeled "Domestic" and 1 is labeled "Foreign".
In the following snippet, I want to plot the average price for each category of the variable foreign using a loop:
sysuse auto, clear
forvalues i=0/1{
local t = foreign[`i']
graph bar (mean) price if foreign == `i', ///
over(rep78, sort(price) descending) asyvars ///
title("`t'") name(p_`i', replace) nodraw
local graphs `graphs' p_`i'
}
gr combine `graphs'
but it does not even display the category value correctly in the title.
What am I doing wrong?
Your code
local t = foreign[`i']
sets the local macro t to the value of the variable foreign first in observation 0 and then in obseration 1: these will be missing and 0, respectively.
What you want is the value label corresponding to the values 0 and 1, which you can obtain with
local t : label (foreign) `i'
Swap this into your code and your graphs will be labelled Domestic and Foreign, respectively.
The syntax of the replacement command may be unfamiliar; macro "extended functions" are described in help extended_fcn.
Note that either of these graph commands
sysuse auto, clear
graph bar (mean) price , ///
over(rep78, sort(price) descending) asyvars over(foreign)
graph bar (mean) price , ///
over(rep78, sort(price) descending) asyvars by(foreign)
uses value labels automatically and produces a combined graph directly. This may not be the main question, but the original code is not a good solution on those grounds.
I have the following model:
Y_{it} = alpha_i + B1*weight_{it} + B2*Dummy_Foreign_{i} + B3*(weight*Dummy_Foreign)_ {it} + e_{it}
and I am interested on the effect on Y of weight for foreign cars and to graph the evolution of the relevant coefficient across quantiles, with the respective standard errors. That is, I need to see the evolution of the coefficients (B1+ B3). I know this is a non-linear effect, and would require some sort of delta method to obtain the variance-covariance matrix to obtain the standard error of (B1+B3).
Before I delve into writing a program that attempts to do this, I thought I would try and ask if there is a way of doing it with grqreg. If this is not possible with grqreg, would someone please guide me into how they would start writing a code that computes the proper standard errors, and graphs the quantile coefficient.
For a cross section example of what I am trying to do, please see code below.
I use grqred to generate the evolution of the separate coefficients (but I need the joint one)-- One graph for the evolution of (B1+B3) with it's respective standard errors.
Thanks.
(I am using Stata 14.1 on Windows 10):
clear
sysuse auto
set scheme s1color
gen gptm = 1000/mpg
label var gptm "gallons / 1000 miles"
gen weight_foreign= weight*foreign
label var weight_foreign "Interaction weight and foreign car"
qreg gptm weight foreign weight_foreign , q(.5)
grqreg weight weight_foreign , ci ols olsci reps(40)
*** Question 1: How to constuct the plot of the coefficient of interest?
Your second question is off-topic here since it is statistical. Try the CV SE site or Statalist.
Here's how you might do (1) in a cross section, using margins and marginsplot:
clear
set more off
sysuse auto
set scheme s1color
gen gptm = 1000/mpg
label var gptm "gallons / 1000 miles"
sqreg gptm c.weight##i.foreign, q(10 25 50 75 95) reps(500) coefl
margins, dydx(weight) predict(outcome(q10)) predict(outcome(q25)) predict(outcome(q50)) predict(outcome(q75)) predict(outcome(q95)) at(foreign=(0 1))
marginsplot, xdimension(_predict) xtitle("Quantile") ///
legend(label(1 "Domestic") label(2 "Foreign")) ///
xlabel(none) xlabel(1 "Q10" 2 "Q25" 3 "Q50" 4 "Q75" 5 "Q95", add) ///
title("Marginal Effect of Weight By Origin") ///
ytitle("GPTM")
This produces a graph like this:
I didn't recast the CI here since it would look cluttered, but that would make it look more like your graph. Just add recastci(rarea) to the options.
Unfortunately, none of the panel quantile regression commands play nice with factor variables and margins. But we can hack something together. First, you can calculate the sums of coefficients with nlcom (instead of more natural lincom, which the lacks the post option), store them, and use Ben Jann's coefplot to graph them. Here's a toy example to give you the main idea where we will look at the effect of tenure for union members:
set more off
estimates clear
webuse nlswork, clear
gen tXu = tenure*union
local quantiles 1 5 10 25 50 75 90 95 99 // K quantiles that you care about
local models "" // names of K quantile models for coefplot to graph
local xlabel "" // for x-axis labels
local j=1 // counter for quantiles
foreach q of numlist `quantiles' {
qregpd ln_wage tenure union tXu, id(idcode) fix(year) quantile(`q')
nlcom (me_tu:_b[tenure]+_b[tXu]), post
estimates store me_tu`q'
local models `"`models' me_tu`q' || "'
local xlabel `"`xlabel' `j++' "Q{sub:`q'}""'
}
di "`models'
di `"`xlabel'"'
coefplot `models' ///
, vertical bycoefs rescale(100) ///
xlab(none) xlabel(`xlabel', add) ///
title("Marginal Effect of Tenure for Union Members On Each Conditional Quantile Q{sub:{&tau}}", size(medsmall)) ///
ytitle("Wage Change in Percent" "") yline(0) ciopts(recast(rcap))
This makes a dromedary curve, which suggests that the effect of tenure is larger in the middle of the wage distribution than at the tails:
I am trying to plot a lorenz curve, using the following command:
glcurve drugs, sortvar(death) pvar(rank) glvar(yord) lorenz nograph
generate rank1=rank
label variable rank "Cum share of mortality"
label variable rank1 "Equality Line"
twoway (line rank1 rank, sort clwidth(medthin) clpat(longdash))(line yord rank , sort clwidth(medthin) clpat(red)), ///
ytitle(Cumulative share of drug activity, size(medsmall)) yscale(titlegap(2)) xtitle(Cumulative share of mortality (2012), size(medsmall)) ///
legend(rows(5)) xscale(titlegap(5)) legend(region(lwidth(none))) plotregion(margin(zero)) ysize(6.75) xsize(6) plotregion(lcolor(none))
However, in the resultant curves, the Line of equality does not start from 0, is there a way to fix this?
Is it recommended to use the following in order to get the perfect 45 degree line of equality:
(function y=x, range(0 1)
Also, how many minimum observations are required to plot the above graph? Does it work well with 2 observations as well?
The reason your Line of Perfect Equality does not pass through (0,0) is because the values for your variable do not contain 0.
The smallest value you will have for rank will be 1/_N. Although this value will asymptotically approach 0, it will never actually reach 0.
To see this, try:
quietly sum rank
di r(min)
di 1/_N
Further, by applying the program code to your data (beginning around line 152 in the ado file and removing unnecessary bits), one can easily see that yord cannot take on a value of 0 without values of 0 for drugs:
glcurve drugs, sortvar(death) pvar(rank) glvar(yord) lorenz nograph
sort death drugs , stable
gen double rank1 = _n / _N
qui sum drugs
gen yord1= (sum(drugs) / _N) / r(mean)
The best way to plot your Equality would be the method from your edit, namely:
twoway(function y = x, ra(0 1))
One quick yet (very) crude fix to force the lorenz curve to start at the origin (if it doesn't already) is to add an observation to the data after obtaining rank and yord, and then deleting it after you have your curve:
glcurve drugs, sortvar(death) pvar(rank) glvar(yord) lorenz nograph
expand 2 in 1
replace yord = 0 in 1
replace rank = 0 in 1
twoway (function y = x, ra(0 1)) ///
(line yord rank)
drop in 1
Like I said, this is admittedly crude and even somewhat ill advised, but I can't see a much better alternative at the moment, and with this method you will not be altering any of the other values of yord by running glcurve on the extrapolated data.