Part 10 (1/2)
In an unpublished study of the graduates of Pratt Inst.i.tute, Dr. D. E. Rice has compared the grades achieved by students in the courses in Mechanical Engineering and Electrical Engineering with the salaries the men were receiving several years after graduation. There were in all six cla.s.ses of men, numbering about forty each--three cla.s.ses from Mechanical Engineering and three from Electrical Engineering, for the years of 1907, 1908, 1909.
The salary reports were asked for in 1913, four to six years after graduation.
The men were ranked according to the grades they received in the eight different subjects included in the curriculum, the grades being 10, 9, 8, and 7, corresponding to the ordinary grade system of A, B, C, D. They were then ranked according to the salary reported at the time of the investigation. Results for each cla.s.s were treated separately so that the time elapsing since graduation was not a factor in the results. The following table gives the results when these two rankings were correlated by two statistical methods of computing correlation.
In every case the correlation between grades and salary is positive, although the coefficients are all small. This means that in the long run there is a general tendency for the good salaries to go to the men whose grades were high, but that there are many exceptions to the rule. Certainly in no cla.s.s is the opposite tendency shown, for the good salaries to go to the poor students. It is probable that the correlations found here are as low as they are partly because in this technical school there is no special effort made to encourage high grades for their own sake, the emphasis being rather on getting a good average rating.
TABLE 18
SHOWING THE CORRELATION BETWEEN SCHOOL STANDING AND SALARIES EARNED IN LATER LIFE (RICE)
See Text for Explanation
------------------------------------------------------------
Correlation by
Correlation by Cla.s.s and Year
Cases
Pearson Method,
Per Cent of Unlike
and P.E.
Signs, and P.E.
---------------+-------+----------------+------------------- Mechanical '07
35
.36 .08
.22 .09 Mechanical '08
41
.25 .09
.34 .08 Mechanical '09
39
.21 .09
.06 .10
Electrical '07
26
.16 .13
.25 .12 Electrical '08
36
.46 .08
.51 .08 Electrical '09
41
.16 .10
.28 .09
Averages
.267
.277 ------------------------------------------------------------
Just what these degrees of correlation mean is made somewhat more apparent if we treat the data in another way. If instead of computing coefficients of correlation we divide each cla.s.s of men into four quartiles, and determine the average salaries of the men in these quartiles, we get very definite results. The upper quartile or group will now contain that fourth of the cla.s.s whose grades were highest. The second, third and fourth quartiles will in turn represent decreasing degrees of academic proficiency. If the average salaries are the same for all quartiles, this will mean that there is no relation between salary and school grades. But if the salary varies with the grades, this will be a significant result.
The actual data are as follows:
TABLE 19
RICE'S DATA PRESENTED IN A REVISED FORM
------------------------------------------------------------
Average Salaries of the Cla.s.s and Year
Cases
--------------------------------------
1st
2nd
3rd
4th
Quartile
Quartile
Quartile
Quartile ---------------+-----+-----------------+--------+----------- Mechanical '07
35
$1800
$1675
$1362
$1387 Mechanical '08
41
1450
1512
1512
1275 Mechanical '09
39
1375
1262
1313
1137
Electrical '07
26
1750
1675
1675
1412 Electrical '08
36
2147
1437
1262
1262 Electrical '09
41
1462
1212
1387