Kit Baum replied to Mark Schaffer:
> Indeed it can be confusing! Mark is absolutely right--you should ADD
> one to bw(), which starts counting from zero, to match lags(). Sorry
> for the added confusion!
I don't know if Jonathan A. Schwabish, who sent the original post, is now
satisfied, but I'm a bit puzzled. This is what I get when using Garrett
and Mitchell's (2001) infamous dataset, applying Kit and Mark's "for N
lags, add one to the bandwidth" formula:
. newey2 growthpc trade fdi unem left spend captax labtax, lag(1)
Regression with Newey-West standard errors Number of obs = 352
maximum lag : 1 F( 7, 344) = 4.89
Prob > F = 0.0000
----------------------------------------------------------------------------
| Newey-West
growthpc | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-----------+----------------------------------------------------------------
trade | .0051762 .0063955 0.81 0.419 -.007403 .0177555
fdi | .1112711 .1114347 1.00 0.319 -.107908 .3304503
unem | -.0917037 .0489144 -1.87 0.062 -.1879127 .0045053
left | -.0011842 .0035009 -0.34 0.735 -.0080701 .0057017
spend | -.0295982 .0455134 -0.65 0.516 -.1191177 .0599213
captax | -.0620164 .0155124 -4.00 0.000 -.0925275 -.0315053
labtax | -.0282463 .0348024 -0.81 0.418 -.0966986 .0402061
_cons | 6.832187 .9175741 7.45 0.000 5.027425 8.636949
----------------------------------------------------------------------------
. ivreg2 growthpc trade fdi unem left spend captax labtax, bw(2) small
Ordinary Least Squares (OLS) regression
---------------------------------------
Autocorrelation-consistent statistics
kernel=Bartlett; bandwidth=2
time variable (t): year
group variable (i): nation
Number of obs = 352
F( 7, 344) = 7.30
Prob > F = 0.0000
Total (centered) SS = 2042.961127 Centered R2 = 0.1708
Total (uncentered) SS = 4004.310028 Uncentered R2 = 0.5769
Residual SS = 1694.045908 Root MSE = 2.2
----------------------------------------------------------------------------
growthpc | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-----------+----------------------------------------------------------------
trade | .0051762 .0073358 0.71 0.481 -.0092525 .019605
fdi | .1112711 .1040054 1.07 0.285 -.0932954 .3158377
unem | -.0917037 .0581893 -1.58 0.116 -.2061553 .022748
left | -.0011842 .0041281 -0.29 0.774 -.0093037 .0069353
spend | -.0295982 .0382442 -0.77 0.440 -.10482 .0456236
captax | -.0620164 .0160886 -3.85 0.000 -.0936608 -.030372
labtax | -.0282463 .0339707 -0.83 0.406 -.0950628 .0385703
_cons | 6.832187 .7036352 9.71 0.000 5.448218 8.216156
----------------------------------------------------------------------------
The coefficients are the same, but the standard errors most certainly
aren't. What's up here? Or, alternatively, what's up with me?
CLIVE NICHOLAS |t: 0(044)7903 397793
Politics |e: [email protected]
Newcastle University |http://www.ncl.ac.uk/geps
References:
Garrett G and Mitchell D (2001) "Globalization, Government Spending and
Taxation in the OECD", EUR J POLIT RES 39(1): 145-77.
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