An illustration of the first kind is found in the early work of the West Virginia Station (Bulletin 60).  With the preconceived notion that hens should have a nitrogenous diet an experiment was planned and conducted as follows: 

One lot of hens was fed corn, potatoes, oats and corn meal.  A contrasted lot reveled in corn, potatoes, hominy feed, oat meal, corn meal and fresh cut bone.  The results were in favor of the latter ration by a doubled egg yield.

To any experienced poultryman the reason is evident.  The variety of the diet and the meat food are what made the showing.

About the same time the Massachusetts Station planned a similar experiment.  The bias was the same, but it took a fairer form.  The hens were both given a decent variety of food and some form of meat.  The bulk of the grain was corn in the carbonaceous, and wheat in the nitrogenous ration.  The results were in favor of the corn.  This astonished the experimenter.  He tried it again and again tests came out in favor of corn.  At last the old theory was revoked, and the fallacy of wheat being essential to egg production was exploded.  If by an irony of fate in the shuffling of the hens, the wheat pen had the first time showed an advantage, the experimenter might have been satisfied and the waste of feeding high priced feed when a better and a cheaper is at hand, might have gone on indefinitely.

Of bias in the interpretation of results all publications are more or less saturated.  A reading of the Chapter on Incubation will illustrate this.  A common error of this kind is the omission of facts necessary to fully explain results.  Items of costs are invariably omitted or minimized.  Food cost alone is usually mentioned in figuring experimenting station poultry profits, which statement will undoubtedly cause a sad smile to creep over the face of many a “has-been” poultryman.

The writer remembers an incident from his college days which illustrates the point in hand.  Let it first be remarked that this was on the new lands of the trans-Missouri Country, where manure had no more commercial value than soil, and is freely given to those who will haul it away.

The professor at the blackboard had been figuring up handsome profits on a type of dairying towards which he wits very partial.  The figures showed a goodly profit, but the biggest expense item—­that of labor—­was omitted.  One of the students held up his hand and inquired after the labor bill.

“Oh,” said the smiling professor, “The manure will pay for the labor.”

When the class adjourned, the student remarked:  “They say figures won’t lie, but a liar will figure.”