Lag/lead correlations in Cross Correlogram
Posted: Thu Mar 26, 2015 3:44 pm
I am using Cross Correlogram with a lag of 10 to identify the highest correlation between two variables. My understanding is that the figures in the tables are the correlation between the two variables (with lag/lead as indicated by i). However, I noticed that other than i=0, the correlations of lag/lead variables do not match exactly the actual correlation -- if I generate the lag variable and calculate the correlation. Could anybody explain to me why? Thank you.
For example
Here is the result of Cross Correlogram:
Date: 03/26/15 Time: 17:12
Sample: 1995Q3 2014Q4
Included observations: 74
Correlations are asymptotically consistent approximations
Q3_9,CILOANYY(-i) Q3_9,CILOANYY(+i) i lag lead
. |**** | . |**** | 0 0.3789 0.3789
. |*** | . |***** | 1 0.2770 0.4601
. |** | . |***** | 2 0.1588 0.5059
. | . | . |***** | 3 0.0432 0.5008
.*| . | . |***** | 4 -0.0530 0.4798
.*| . | . |**** | 5 -0.1241 0.4264
**| . | . |**** | 6 -0.1773 0.3585
**| . | . |*** | 7 -0.2057 0.2849
**| . | . |** | 8 -0.2227 0.1978
**| . | . |*. | 9 -0.2238 0.0905
**| . | . | . | 10 -0.2187 -0.0220
If I genr q3_9_lag1=@lag(q3_9,1), and correlate q3_9_lag1 with ciloanyy, I got 0.454389, which is different from 0.4601 in the above table.
For example
Here is the result of Cross Correlogram:
Date: 03/26/15 Time: 17:12
Sample: 1995Q3 2014Q4
Included observations: 74
Correlations are asymptotically consistent approximations
Q3_9,CILOANYY(-i) Q3_9,CILOANYY(+i) i lag lead
. |**** | . |**** | 0 0.3789 0.3789
. |*** | . |***** | 1 0.2770 0.4601
. |** | . |***** | 2 0.1588 0.5059
. | . | . |***** | 3 0.0432 0.5008
.*| . | . |***** | 4 -0.0530 0.4798
.*| . | . |**** | 5 -0.1241 0.4264
**| . | . |**** | 6 -0.1773 0.3585
**| . | . |*** | 7 -0.2057 0.2849
**| . | . |** | 8 -0.2227 0.1978
**| . | . |*. | 9 -0.2238 0.0905
**| . | . | . | 10 -0.2187 -0.0220
If I genr q3_9_lag1=@lag(q3_9,1), and correlate q3_9_lag1 with ciloanyy, I got 0.454389, which is different from 0.4601 in the above table.