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st: RE: Creating a dummy set of values to use in a graph in the presence of under-reported values

 From Tim Evans To "'statalist@hsphsun2.harvard.edu'" Subject st: RE: Creating a dummy set of values to use in a graph in the presence of under-reported values Date Fri, 29 Jun 2012 11:13:07 +0100

```Hi all,

I was probably trying to over complicate this. I just wanted to plot a straight line between the last year with full data before the missing data and the first full year of data following the missing period. I can do this quite easily in my graph by plotting only these two points:

levelsof sex, local(levels)
foreach l of local levels {
su crude if sex==`l'
line crude yydx if sex=="m", lpattern("l") || line crude yydx if sex=="f",  lpattern("_") || /*
*/ line crude yydx if sex=="m" & inlist(yydx, 1989, 1994), lpattern("._.") lcolor(gs10) || /*
*/ line crude yydx if sex=="f" & inlist(yydx, 1989, 1994), lpattern("._.") lcolor(gs10) xaxis(1 2) /*
*/ yscale(range(`= 50 * ceil(r(max)/ 50)')) /*
*/ ylabel(0(50) `= 50 * ceil(r(max)/ 50)' , gmax  angle(horizontal) format(%3.0f)) /*
*/ xline(1988 1994) /*
*/ xlabel(1988 1994, axis(1)) xtitle("Year", size(small) axis(2)) xtitle("", axis(1)) plotregion(lstyle(none)) /*
*/ label(2 "Males") label(3 "Females") order(1 2)) /*
*/ legend(region(lstyle(none)) rows(1) size(small) lcolor(none))
}

Best wishes

Tim

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Tim Evans
Sent: 29 June 2012 09:44
To: 'statalist@hsphsun2.harvard.edu'
Subject: st: Creating a dummy set of values to use in a graph in the presence of under-reported values

Hi all,

I am plotting incidence of a type of cancer by year and by sex between 1985 and 2009 in Stata 11.2. Between 1990 and 1994 I have a lot of missing data, and so the incidence appears to fall, even though the overall trend is going up. What I would like to do is generate a dummy data series with values that are based upon the difference in rates between the last full year of data before the missing data and the first year of full data following reinstatement of full data capture and then use these data to be able to plot in my twoway graph. So for instance, if I had 5 years missing data, and the rate increased by 10 from the two points either side of the missing data, I could generate dummy values which increase in increments of 2 per year.

I always know when the missing years of data are.

Alternatively, I could try and overlay a single line between the two points in my graph - but I don't know how I might do this.

My data structure are as follows:

yydx sex crude_rate
1988 m   100
1989 m   110
1990 m   30
1991 m   35
1992 m   36
1993 m   36
1994 m   36
1995 m   120
1996 m   130
1997 m   136
1988 f   200
1989 f   210
1990 f   130
1991 f   135
1992 f   136
1993 f   136
1994 f   136
1995 f   220
1996 m   230
1997 m   236

I am graphing the data like this:

su crude if sex==`l'
line crude yydx if sex=="m", lpattern("l") || line crude yydx if sex=="f",  lpattern("_") xaxis(1 2) ,  /*
*/ yscale(range(`= 50 * ceil(r(max)/ 50)')) /*
*/ ylabel(0(50) `= 50 * ceil(r(max)/ 50)' , gmax  angle(horizontal) format(%3.0f)) /*
*/ xline(1988 1994) /*
*/ xlabel(1988 1994, axis(1)) xtitle("Year", size(small) axis(2)) xtitle("", axis(1)) plotregion(lstyle(none)) /*
*/ label(2 "Males") label(3 "Females") order(1 2)) /*
*/ legend(region(lstyle(none)) rows(1) size(small) lcolor(none))
}

Any help really appreciated.

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```