Reprinted from the Proceedings of the NATIONAL ACADBMV OF SCIENCES, 

 Vol. 7, No. 7, pp. 213-219, July, 1921. 



THE PREDICTION OF ANNUAL EGG PRODUCTION FROM THE 

 RECORDS OF LIMITED PERIODS 



BY J. ARTHUR HARRIS, W. F. KIRKPATRICK AND A. F. BL,AKESUSE 



STATION FOR EXPERIMENTAL EVOLUTION, CARNEGIE INSTITUTION, AND THE STORKS 

 AGRICULTURAL EXPERIMENTAL STATION 



Communicated by C. B. Davenport, March 12, 1921 



For the past several years the writers have been considering the possi 

 bility of predicting the annual egg production of the domestic fowl from the 

 records of short periods of time. Such records may be determined by trap- 

 nesting, or by the use of other criteria when the maternity of the eggs is not 

 required for breeding purposes. 1 



The first definite step in the direction of the use of the egg record of a 

 short period for the prediction of the production during a subsequent or a 

 longer period was, as far as we are aware, taken in 1917 when it was shown 2 

 that in a heterogeneous series of birds such as are submitted by practical 

 breeders in egg laying contests, the October egg production is correlated 

 with that of every other month of the year. The investigation was carried 

 much further in a second memoir 3 in which the correlations between the 

 records of the individual months and the production of the whole year, 

 between the records of the individual months and those of the remaining 

 11 months of the year, and between the production of 5 of the individual 

 months and the production of all the other individual months, were pub 

 lished for two series of birds. In this paper the equations for the prediction 

 of total annual production from the record of the individual months were 

 given. 



Our purpose here is to state briefly the results of a first test of the possi 

 bility of utilizing the linear regression equation (which is strictly valid 

 only for the population from which it is deduced) for the prediction of the 

 records of the birds of a flock the performance of which is unknown as far 

 as the determination of the constants of the equations is concerned. 



