Filling quarterly series backward

[Abdan Syakura]

Hi all,

Could you please help how to fill a quarterly series backward by using the annual growth rate? I have an annual growth rate for quarterly data and the level value in the last observation year. So I want to extend the series backward by using the growth rate data.

Here is the crude code I tried to do, but it says "is not a valid command name"

forv i = 0/79 {
    replace gdpreal = gdpreal[_N-`i']/((gdpgrw[_N-`i']/100)+1) in [_N-4-`i']

}

Here is the data. Thank you for your help.

* Example generated by -dataex-. To install: ssc install dataex
clear
input float(quarter gdpgrw gdpreal)
160  4.1044025       .
161   5.144167       .
162  4.0468783       .
163   6.406423       .
164   3.960815       .
165   5.056377       .
166  3.6153526       .
167  1.6090896       .
168  2.9461794       .
169  4.1493363       .
170    5.09661       .
171  4.1578083       .
172    4.67788       .
173   4.338862       .
174  4.2635226       .
175  4.4931536       .
176  4.0991983       .
177  4.3877597       .
178   4.498116       .
179   7.158496       .
180   5.964968       .
181   5.871259       .
182   5.838213       .
183   5.106621       .
184   5.127187       .
185   4.933375       .
186   5.864007       .
187   6.056419       .
188   6.055137       .
189   6.726797       .
190   6.744428       .
191   5.842161       .
192   6.218357       .
193   6.302651       .
194   6.254865       .
195   5.282507       .
196   4.520359       .
197   4.135784       .
198  4.2692556       .
199   5.600275       .
200   5.989302       .
201   6.294885       .
202    5.80689       .
203    6.80662       .
204   6.458018       .
205   6.421766       .
206    6.25211       .
207   6.189622       .
208   6.217451       .
209   6.273388       .
210   6.073948       .
211   6.028776       .
212    5.76382       .
213   5.649806       .
214   5.552942       .
215   5.618915       .
216      5.136       .
217   5.002102       .
218   4.965033       .
219   5.036791       .
220   4.831236       .
221  4.7403145       .
222   4.779496       .
223   5.152625       .
224   4.943421       .
225    5.21465       .
226   5.033505       .
227   4.938896       .
228   5.008361       .
229   5.012552       .
230   5.064764       .
231   5.189744       .
232    5.06912       .
233   5.269417       .
234   5.173195       .
235   5.181314       .
236   5.061957       .
237   5.052571       .
238   5.009831       .
239   4.955665       .
240  2.9656055 2703033
241  -5.323691 2589789
242  -3.488022 2720492
243 -2.1665256 2709741
end
format %tq quarter

[Hemanshu Kumar]

Try:

forv i = 0/79 {
    replace gdpreal = gdpreal[_N-`i']/((gdpgrw[_N-`i']/100)+1) in `=_N-4-`i''
}

[Abdan Syakura]

Thanks a lot!