76 Agricullural Research and Produclivity 



lolal value of the contribution ofa publication is $66,285 in wheat 

 and S66,443 in maize, results that are surprisingly close. The dis- 

 tribution of the economic contributions among their components 

 is also very similar in the two crops. However, these estimates, 

 unlike those of the linear model, do not incorporate any deflating 

 procedure. They imply that the contribution of a unit of 

 knowledge is proportional to the country's total output value of 

 the crop, regardless of the diversity of agricultural production 

 conditions. 



Expenditure per publication is estimated in chapter 2 to range 

 from U.S.$30,000 to $350,000, with values for the high publishing 

 countries around $100,000. In the absence of obsolescence, the 

 figures for the yield regressions in table 4.4, are flow values of per- 

 manent-income streams.'^ It is unrealistic to assume that 

 knowledge is not subject to obsolescence and depreciation, but 

 even if these streams last for only twenty years, the present sam- 

 ple period, the values in table 4.4 imply substantial returns to in- 

 vestment in agricultural research. 



This is not the proper framework to attempt a full-fledged 

 calculus of growth accounting" of the relative contributions of 

 different factors to the growth rates in wheat and maize produc- 

 tion. A rough indication of the magnitudes involved can, 

 however, be obtained. In the double-log formulation of (4.13) 



where R stands for the change in the other variables. The average 



value for -jy- is approximate 10 percent both in wheat and maize. 



Taking 72 and 73 from the regressions without borrowing (ta- 

 ble 4.2 regression 4, table 4.3 regression 4) we find that the con- 

 tribution of K, the indigenously created knowledge, to growth 

 was 23 percent in wheat and 33 percent in maize of the "con- 

 tribution'' of the time variable. 



13. To the extent that obsolescence took place over the sample period, the esti- 

 mated coefficients are adjusted for it, and if obsolescence will continue at the 

 same rale, ihse estimates do represent permanent income streams. 



