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The Act of March 3, 1919, provided that “Inquiries shall be made as to the quantity of land reclaimed by irrigation and drainage and the crops produced; also as to the location and character of irrigation and drainage enterprises, and the capital invested in such enterprises.” Statistics concerning drainage had not been gathered previously, but data relative to irrigation had been collected by the eleventh, twelfth, and thirteenth censuses. The data collected in 1920 show that drainage and irrigation are not unimportant either as regards area involved and capital invested or as compared with other statistics heretofore collected by the Census and authorized by the proposed statute.
The act providing for the fourteenth census of agriculture was much more specific with regard to the various items to be covered. It reads as follows:
“The schedules relating to agriculture shall include name, color, sex, and country of birth of occupant of each farm, tenure, acreage of farm, acreage of woodland, value of farm and improvements, and the encumbrance thereon, value of farm implements, number of livestock on farms, ranges, and elsewhere, and the acreage of crops and the quantities of crops and other farm products for the year ending December 31 next preceding the enumeration. Inquiries shall be made as to the quantity of land reclaimed by irrigation and drainage and the crops produced; also as to the location and character of irrigation and drainage enterprises, and the capital invested in such enterprises."
It would appear desirable to make these more specific provisions and to modify the details somewhat so as to read as follows:
“The schedules relating to agriculture shall include name, color, sex, and country of birth of occupant of each farm, tenure, acreage of farm, acreage of pasture and woodland, value of farm and improvements, and the encumbrance thereon, number, kind, and value of principal classes of farm implements, number and kind of tractors, number of livestock on farms, ranges, and elsewhere, the acreage of crops and the quantities of crops and other farm products produced and quantity sold or to be sold and amounts expended during the year for feed, fertilizer, building materials, machinery, and other important factors of production. Inquiries shall bé made as to the quantity of land reclaimed by irrigation and drainage and the acreage and quantity of crops produced on such land; also as to the location and character of irrigation and drainage enterprises, and the capital invested in such enterprises."
The reasons for some of the modifications suggested in these provisions will appear hereafter in the discussion of the census of distribution.
I. DATE OF THE AGRICULTURAL CENSUS
The bill as it stands provides that a census of population shall be taken as of April 1 and a census of agriculture as of November 1 in the preceding year. However, for purposes of economy and other reasons, it appears to be proposed that the two censuses shall be taken at the same time and that the date for both shall be April 1.
It is not our purpose to enter into the consideration of the advantages and disadvantages of taking a population census as of the date mentioned, but there are very strong reasons why changing the date of the agricultural census to April would most seriously impair the value of the statistics obtained and do a great deal of injury to the work of those persons who are engaged in interpreting the statistics obtained by the agricultural census, reaching conclusions with regard to the economic status of agriculture, and employing the census statistics as a basis for the various current estimates which have to be made from time to time. So serious are these objections to April 1 as a date for the agricultural census that if it appears essential to take the population census as of that date, then it is most desirable to separate the two censuses and to take the census of agriculture as of some date not later than the first of the year. The additional cost involved would be fully justified in order to avoid the serious impairment of the value of the statistics of agriculture which would result from changing the date of enumeration to April 1.
It seems desirable to set forth the reasons for this opinion at some length: '
Comparability.–From the standpoint of practical statistical procedure, and as the result of many years of experience with agricultural statistics, we can assert without question that in order for the census or other statistical inquiry to be comparable with the preceding inquiry of the same nature, the two inquiries must be taken under as nearly as possible the same identical conditions. Differences in the form of questions asked, the time of the inquiry and other details of procedure which, to the uninitiated, seem trivial and insignificant, have been found to have a vital influence on the results obtained, and to distort them to such an extent as at times to destroy the usefulness of the inquiry. In fact, the various changes that have already occurred in the dates of the agricultural censuses have left statisticians very much in the dark as to the comparability of certain items. However, changing the date to November 30 would exert à relatively small influence on comparability as compared with the more radical change to April 1, and would involve certain advantages which will be mentioned hereafter.
CONFUSION IN CROP STATISTICS LIKELY TO RESULT FROM CHANGING THE DATE
TO APRIL 1
The taking of a census on April 1 is likely to cause great confusion in the enumeration of fall-planted crops because of confusing the acreage harvested the previous year with that planted in the previous year, but harvested in the year enumeration is made. This confusion frequently appears in schedules received by the Department of Agriculture in the early spring. If the census is taken on April 1 in the Southern States, farmers will be supposed to be reporting on wheat, rye, oats, and barley planted a year and a half previously and harvested for nearly a year. The new crop planted the previous fall will be approaching harvest or actually harvested on April 1, and there is almost sure to be a mix up in the figures reported.
CONFUSION IN LIVESTOCK ENUMERATION RESULTING FROM CHANGE OF DATE
Changing the date of the census to April 1 will also result in a very great deal of confusion in the enumeration of livestock.
Census figures of livestock are inventories giving the numbers of the different species by classes as of a given date. Their value as showing the situation of the livestock industry depends upon their adequacy, accuracy, and comparability with previous inventories. Any material change in the date of the inventory tends to decrease the value of the information. Any change in date that destroys the comparability of the various classes of the different species tends further to reduce the value of the inventory.
The Department of Agriculture has been issuing estimates of livestock on farms as of January 1 since 1867, and all statistics having to do with livestock production, marketing, slaughter and movement are organized on a calendar year basis. Since these estimates of the department are the official figures of livestock numbers in intercensal years, it is highly important that this series be continued on its present basis, which gives inventory numbers at the beginning of the calendar year.
In addition to these estimates of inventories the department has undertaken to estimate the amount and value of livestock production by States for calendar years. These estimates include balance sheets by States showing the number on hand at the beginning of the year, the number born and the number brought into the State as items of increase; and the number marketed, the number slaughtered locally and on farms, and death losses as items of decrease. From these balance sheets the value of production is computed. This work requires dependable inventory figures at the beginning and end of the year.
To be of great significance in showing changes in livestock production inventory figures for different species should be by classes. This need was recognized by the Census Bureau before the 1900 enumeration was made, and from 1900 to 1925 the enumeration of livestock has been by classes. Any change in the census date that destroys the comparability of these classes destroys largely the value of the enumeration,
To understand how changes in dates destroy the comparability of census enumerations the case of milk cows may be considered. In 1900 the inquiry covered “cows kept for milk 2 years old and over" on June 1. This would include all cows milked and heifers 2 years old June 1 that were being milked but not heifers over 2 years that had not freshened. The heifers included would be largely 24 to 27 months old.
In 1910 the inquiry covered “cows and heifers kept for milk, born before January 1, 1909." This classified as milk cows all animals over 1572 months of age, and the resulting figures were not at all comparable with the 1900 figures.
In 1920 the census tried to separate cattle into dairy cattle and beef cattle, and the figure of dairy cows 2 years old and over January 1, was considered as the figure representing milk cows. A similar attempt was made in 1925, but the figures of dairy cows 2 years old and over January 1 were not at all comparable to the similar figures for 1920, due to change in the form of inquiry and to changes
in the cattle situation. Neither the 1920 nor the 1925 figures of all cows (both for milk and not for milk) are comparable with those of 1910, but they are somewhat comparable with those of 1900.
The estimates of the department cover cows and heifers kept for milk 2 years old and over, January 1, and a separate estimate is made of heifers 1 to 2 years old being kept for milk cows. These estimates are based upon the 1925 census figures of "cows milked" in 1924 related to total cows and heifers 2 years old and over January 1.
If, however, the census date is changed to April 1, in 1930, no arrangement of questions can get figures comparable to the present estimates. Even if the schedule should be made to include heifers born the previous year (1929) to be kept for milk cows as was done in 1910, this would only include heifers that were under 1 year, that is, heifer calves, January 1. To get a figure covering the department's estimate of heifers 1 to 2 years old, January 1, being kept for milk cows, a separate question would have to be asked as to heifers born in 1928. Figures covering animals included in the present estimate of cows and heifers 2 years old and over for milk, would require a question on such animals born before January 1, 1928. Most persons familiar with livestock reports and livestock records will agree that the inclusion of such dates would lead to endless confusion and give results of little value as showing actual classification. Since there is a slaughter of cows and heifers probably exceeding 2,000,000 head between January 1 and April 1, a large part of which are dairy cows, and an unknown number of deaths, figures of numbers April 1, even if it could include the same classification, would not be comparable with a January 1 estimate.
With hogs, an April 1 enumeration, regardless of the manner in which the schedule was arranged, would not get figures at all comparable with January 1 numbers. The 1920 and 1925 schedules of January 1, obtained the number of sows and gilts for breeding, the number of pigs under 6 months, which gives a complete enumeration of the fall pig crops of the previous year; and other hogs over 6 months, which gives an enumeration of the spring pig crop of the previous year, less the slaughter during the last three months of the previous year. An April 1 enumeration only gets sows and gilts for spring farrow, which will be somewhat comparable with a similar figure January 1, and April 1 which will be only a part of the pigs born in the spring of 1930 and no indication of total spring crop of that year, and all other hogs which will be made up of a remnant of the spring crop of 1929 and a part of the fall crop of 1929, but in no case an indication of the size of either crop. The 1920 enumeration, if made as of April 1, will not show in any manner what changes in hog production have taken place from 1920 to 1930. There is a total slaughter of over 20,000,000 hogs, and an unknown death loss between January 1 and April 1, which hogs were on farms January 1, and will not be on April 1.
A similar showing can be made for other species of livestock. For example, a January enumeration of sheep will show around 2,500,000 sheep and lambs in Colorado, while an April 1 enumeration would show only about 1,000,000 headthe difference is due to the 1,500,000 lambs on feed January 1 which will be largely marketed by April 1. Nebraska, Iowa, Illinois, and other heavy lambfeeding States would show large decreases for the same reason.
In short, a careful study of the situation leads to the conclusion that an April 1 enumeration of livestock in 1930 will be of little value as showing the trend of livestock production from 1920 to 1930, except with horses and mules, will be of little use to the Department of Agriculture for checking estimates of numbers January 1, will bring further confusion into the series of census enumerations and will be entirely unsatisfactory to all interests connected with livestock production, marketing, and slaughter who have occasion to use census figures for studying conditions in the industry.
In general, agricultural statisticians have recognized the importance of taking the livestock census as nearly as possible at the time of the year when the livestock crop of the year have been largely disposed of and before the birth of a new crop. It has generally been recognized that this date was at or near the first of the year. In planning the world census of agriculture, which it is hoped will be taken in 1930 and concerning which favorable replies had been received from 51 governments by March 1, 1926, it was agreed by the various statisticans concerned that the best date for this world census would be January 1, and that so far as practicable an effort would be made to obtain agreement on that date.
IV. LOSS OF ACCURACY DUE TO LAPSE OF TIME
Without question, the change of the date of the agricultural census to April 1 will seriously affect the accuracy of data reported on for the preceding crop year. In the analysis of data compiled from schedules in the Division of Crop and Livestock Estimates the tendency of farmers to forget some of the details of their farming operations is so common that we have come to use a term for describing this phenomenon which we call “memory bias.” Not only has it become necessary to recognize the existence of this bias and to try to make allowance for it in connection with the preparation of estimates, but it has actually been found necessary to measure the bias. We are advancing no theory as to the underlying causes of this bias, nor do we criticise farmers for their apparent lack of memory concerning farm operations.
We make no implication that they are either ignorant, uneducated, careless, or negligent. It is the viewpoint of the staff of the Division of Crop and Livestock Estimates that we must take the reports as they come to us and so treat them that they may yield as accurate and correct a foundation for the preparation of estimates as lies in our power to make. It may be well to present a few examples of memory bias.
In connection with its estimates of the production of cotton the Bureau of Agricultural Economics makes inquiry of its crop reporters as to the average yield per acre of cotton on December 1 of each year and also on March 1 of the succeeding year. The average yield per acre as reported by the very same list of cotton-crop reporters totaling about 6,000 is as follows:
TABLE 1.-Yield of cotton reported to Department of Agriculture for 1925 and 1926
crops, in pounds per acre
It will be noted that there is a material spread between the average of the reports at the earlier and later dates.
In Table 2 is presented a summary of the reports of 837 farmers in Wisconsin, relating to acreages and livestock on their farms on May 15, 1921. In the first column are shown the totals reported by these farmers on that date. A year later they were asked to report these same items, not only as of May 15, 1922, but also for a year earlier, that is, May 15, 1921. For example, 837 identical reporters reported on May 15, 1921, that they had 13,747 acres of corn planted on that date. A year later they reported that they had 14,090 acres on their farms a year preceding the time when the report was made. Attention is directed to the fact that for not a single crop are the totals alike. Examination of these data indicates that some rye was remembered a year later as wheat, and considerable timothy was remembered as clover. The memory bias of one year on dairy cows was only 0.4 of 1 per cent but for dairy heifers it was 22.9 per cent. (Table 2.)
TABLE 2.-- Acres of crops and numbers of livestock on farms of 837 identical crop
reporters in Wisconsin on May 15, 1921
A study of 784 identical farms for the preceding year, that is, relating to May 15, 1920, and as reported a year later, showed an almost identical situation with respect to memory bias. In Table 3 similar comparisons are given showing historical and current replies for sheep as reported by Utah farmers for three years, and in Table 4 similar comparisons for Utah sheep as between July and January reports. In this case the farmers were asked to report concerning sheep shorn six months or more previously. Much the same situation is noted. (Tables 3 and 4.)
TABLE 3.-Number of sheep reported by Uiah farmers, January 1
COMPARISONS OF CURRENT REPORTS OF INVENTORY NUMBERS OF TOTAL SHEEP