Hi Statalist


I use panel data of couples, each observation (is one household defined by the variable idhous) has variables for the man and woman on income and so on. I want to now compare how the birth of the firstborn child affects the previously (2 years before birth, variable called incomediff2) measured within couple wage gap. For this, I generated the variable eventtime, which measures the years relative to the birth of the child. To make my analysis more interesting, i divided the couples into two groups: couples that are politically left or right (dummy variable left=1 if left and =0 if right). I am running the xtreg command and want to find out wether the difference in the regression coefficients for the group left or right is statistically significant. I am aware that i cant use suest. So I’ve tried to use an interaction term but i dont receive the same coefficients when i use the interaction term and when i dont. Can someone please tell me where I am going wrong?


Commands im using

eststo DL: xtreg incomediff incomediff2 i.eventtime i.year edgap agegap edyearf childcare, vce(cluster idhous)

eststo DL: xtreg incomediff incomediff2 i.eventtime i.year edgap agegap edyearf childcare (c.incomediff2 c.eventtime c.year c.edgap c.agegap c.edyearf c.childcare)#left, vce(cluster idhous)


I hope i explained my problem well enough.

PS: beginner stata user

Thanks!

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input long idhous float(incomediff incomediff2 edgap agegap left)
4291    .8025513          .   5 -3 1
4291           .          .   5 -3 1
4291           .          .   5 -3 1
4291   1.2001867          .   5 -3 1
4291           .          .   5 -3 1
13374   -.0902532 -.02123192  -4  4 1
13374   .04665501 -.02123192  -4  4 1
13374    1.216366 -.02123192  -4  4 1
13374   1.7034093 -.02123192  -4  4 1
13374    1.288267 -.02123192  -4  4 1
13374   1.4012942 -.02123192  -4  4 1
13374    1.411276 -.02123192  -4  4 1
13381    .5420939          .   0 -9 1
13381    .6947426          .   0 -9 1
13381           .          .   0 -9 1
13381           .          .   0 -9 1
14241    2.187799          .   2  2 1
14241           .          .   2  2 1
14241   .55151635          .   2  2 1
14241   .45938775          .   2  2 1
14241    .8455062          .   2  2 1
14241   .52631915          .   2  2 1
14241     .600426          .   2  2 1
15222   .05180164  .05784675  -6  0 0
15222   .53180295  .05784675  -6  0 0
15222    .3193598  .05784675  -6  0 0
15222    .9885963  .05784675  -6  0 0
15222    .6885488  .05784675  -6  1 0
16731   -.1670527 -.08474053   3  4 1
16731   .04729639 -.08474053   3  4 1
16731    .3838619 -.08474053   3  4 1
16731   .09983494 -.08474053   3  4 1
16731   .23967063 -.08474053   3  4 1
16731    .3762996 -.08474053   3  4 1
16731    .4074799 -.08474053   3  4 1
21442    .7139507          .   0 -2 1
21442    .6127079          .   0 -2 1
21442   2.1356988          .   0 -2 1
21442           .          .   0 -2 1
21442           .          .   0 -2 1
21442   3.1716845          .   0 -2 1
21442   3.5162594          .   0 -2 1
21442           .          .   0 -2 1
21442           .          .   0 -2 1
26031  -.26516086 -.20032717   0  0 1
26031   -.3323401 -.20032717   0  0 1
26031  -.17684834 -.20032717   0  0 1
26031    .2048285 -.20032717   0  0 1
26031    .5872296 -.20032717   0  0 1
26031    .8075491 -.20032717   0  0 1
26031    .1531501 -.20032717   0  0 1
26031    .2273172 -.20032717   0  0 1
29061           .          .   8  4 0
29061           .          .   8  4 0
29061   4.4611197          .   8  4 0
29061   2.6433666          .   8  4 0
29061    2.965289          .   8  4 0
29061   2.7983994          .   8  4 0
29061    2.873498          .   8  4 0
29061    2.839221          .   8  4 0
29061   2.1390777          .   8  4 0
35404    .1898665  .08865514   0  3 1
35404   .13464524  .08865514   0  3 1
35404           .  .08865514   0  2 1
36602           .          .   6  0 0
36602           .          .   6  0 0
36602           .          .   6  0 0
37591    .2025216  .02059248   2  2 0
37591   1.7441094  .02059248   2  2 0
37591   1.4136633  .02059248   2  2 0
37591   1.1085622  .02059248   2  2 0
37591   1.0557346  .02059248   2  2 0
37591    1.038873  .02059248   2  2 0
37592  -.01922184  -.2221554  -6  3 1
37592    .7027051  -.2221554  -6  3 1
37592   1.2039472  -.2221554  -2  3 1
37592   1.1006347  -.2221554  -2  3 1
37592   1.1006347  -.2221554  -2  3 1
37592   1.2709785  -.2221554  -2  3 1
37592   1.3131486  -.2221554  -2  3 1
37592   1.1685479  -.2221554  -2  3 1
37812  -.11154032   .3174509   0  2 1
37812 -.008959652   .3174509   0  2 1
37812 -.002995479   .3174509   0  1 1
41365           .          .   0 -5 1
48152    .6261821   .5037338 -11  3 1
48152    .5625459   .5037338 -11  3 1
48152  -.04564056   .5037338 -11  3 1
48152   .05061904   .5037338  -9  3 1
48951           .          .  -6 15 0
48951   1.5004704          .  -6 15 0
48951           .          .  -6 15 0
48951           .          .  -6 15 0
48951           .          .  -6 15 0
48951           .          .  -6 15 0
48951   2.3277872          .  -6 15 0
48951   2.3141751          .  -6 15 0
48951   2.1364963          .  -6 15 0
48951   2.3141751          .  -6 16 0
50092  -.04645612  .08142643   0  2 0
end
label values idhous IDHOUS99