regression discontinuity error no observations

[Sabrina Solanki]

Hi,

I ran the following code using the data (below). This is the first time that I have used dataex so please let me know if I didn't post correctly.

rd grade treatment assignment

and I received the follow error message: no observations.

I would appreciate any suggestions to fix this problem. I think it has something to do with my outcome being ordinal and not continuous.

* Example generated by -dataex-. To install: ssc install dataex
clear
input float(id grade) long treatment float assignment
  1 3.7 0   10
  2   4 0   80
  3 2.7 1  -20
  4   2 0   20
  5   4 0  110
  6   4 0   30
  7 2.3 0  100
  8   4 0    .
  9 2.7 1  -30
 10   3 0   60
 11   4 0   60
 12   4 1  -20
 13   1 0  -90
 14   4 1    .
 15   4 0    .
 16   4 1  -20
 17   3 1  -50
 18   1 1 -150
 19   4 0  140
 20 1.7 1 -170
 21 3.3 0  170
 22   3 1  -20
 23   1 1  -60
 24   . 0   70
 25 3.3 0   90
 26 1.3 1  -60
 27   4 0  140
 28 3.3 1  -70
 29   4 1  -10
 30   2 1 -230
 31 3.7 0   10
 32 3.7 1 -140
 33 3.7 1  -10
 34 3.7 0   10
 35 2.7 0   20
 36   4 0   40
 37   4 0  160
 38   4 0   80
 39 3.3 0  120
 40   4 0   90
 41   3 1  -90
 42 1.3 1  -30
 43 1.3 1  -70
 44 3.7 1 -120
 45 2.3 0   40
 46   3 0  -50
 47   4 0   90
 48 3.7 0  -10
 49 1.7 0   80
 50 2.7 0  160
 51 2.7 1  -30
 52 3.7 0   20
 53   4 0  130
 54   4 0   10
 55   3 0   30
 56   4 0   30
 57 3.7 0   70
 58 3.3 0  -10
 59 3.7 0    0
 60 2.7 1  -10
 61 3.3 1  -20
 62 2.7 0    .
 63   3 1  -50
 64   4 0   20
 65   2 0  -20
 66 2.3 0   10
 67 1.7 1  -60
 68   4 0    .
 69   4 0  180
 70   4 0   10
 71 2.3 1 -110
 72   3 1  -80
 73 3.3 1  -30
 74 3.3 0  -40
 75   4 1  -80
 76   4 0    .
 77   3 1 -130
 78 1.3 1 -140
 79 1.7 0   20
 80   2 1  -60
 81 1.7 0   90
 82 1.7 1 -100
 83 3.7 0    .
 84   2 1 -100
 85   4 0   10
 86   2 0    0
 87   4 0    .
 88 2.7 0   70
 89 2.3 0   90
 90 3.7 1  -60
 91 3.7 1  -10
 92 3.3 1  -80
 93   2 1 -120
 94   . 0    0
 95   4 0  140
 96   4 0   70
 97 3.3 0    0
 98 3.7 0   90
 99 3.7 1  -90
100 3.3 1 -100
end
label values treatment treatment
label def treatment 0 "untreated", modify
label def treatment 1 "treated", modify

[William Lisowski]

Help!

Apparently the rd command is not a part of the official Stata release. My usual tools for finding commands are not helping me here.

Please review the Statalist FAQ linked to from the top of the page, noting especially the following advice.

12.1 What to say about your commands and your problem

Say exactly what you typed and exactly what Stata typed (or did) in response. N.B. exactly!

If you are using user-written commands, explain that and say where they came from: the Stata Journal, SSC, or other archives. This helps (often crucially) in explaining your precise problem, and it alerts readers to commands that may be interesting or useful to them.

Added: OK, I found the command in SSC and installed it, and ran it on the data you provided. Here is what the command tells us in full.

. rd grade treatment assignment 
Three variables specified; jump in treatment  
at Z=0 will be estimated. Local Wald Estimate
is the ratio of jump in outcome to jump in treatment.

 Assignment variable Z is assignment
 Treatment variable X_T is treatment
 Outcome variable y is grade

no observations
r(2000);

So it appears the jump in treatment will be estimated at assignment=0. But in the data, all the treated observations have a value of assignment < 0. To me, this along with the error message suggests that your data do not meet the assumptions of the command.

[Sabrina Solanki]

I am using regression discontinuity to estimate treatment effects on outcome.

ssc inst rd, replace
net get rd