United States yearbook - 1982 (1)

Statistical Methodology and Reliability 919
DATA COLLECTION AND
IMPUTATION PROCEDURES
INFORMATION ON ERRORS IN THE DATA
Estimates of sampling
error
Other (nonsampling)
errors
SOURCES OF ADDITIONAL
MATERIAL
Statistical copies of import
entry documents, received on
a daily basis from Customs
ports of entry throughout the
country, are subjected to a
monthly processing cycle.
They are fully processed to
the extent they reflect Items
valued at $251 and over.
Estimated CV for world area
and country totals less than
.1 % for totals over $20
million; less than .5% for
totals between $1 million and
$20 million; and less than
possible errors due to
rounding for values less than
$1 million.
Verification of statistical data
reporting tty Customs officials
prior to transmittal and a
subsequent program of
clerical and computer checks
hold nonsampling errors
arising from reporting and/or
processing errors to a
minimum.
U.S. Bureau of the Census,
U S . G e n e ra /Im p o rts ,
S c h e d u le A , C o m m o d ity b y
C o u n try , FT 135.
Mail questionnaire to stratified
sample (approx. 26%) of
(arms; shorter questionnaire
to others on mail list.
Nonrespondent followup by
letters and phone calls.
Published county data ■
adjusted for mail list
nonresponse. Supplemental
direct enumeration sample
provides estimates for farms
not on mail list
Standard errors by county
and State for farm acreage,
value of (and and buildings,
various crop and livestock
values given In Appendix A
tables of each 1978 State
volume. The estimated CV for
U.S. number of farms Is .22%
and land in farms is .04%.
Estimates of undercoverage
of farms (chiefly small farms)
was 3.4% nationally.
Adjustment for farm
nonresponse as a percent of
the U.S. total represented
8.5% for number of farms,
4.6% for land In farms, and
3.9% for value of products
sold.
U.5. Bureau of the Census,
C e n s u s o f A g ric u ltu re , 1976,
State and county volumes.
Data collection by persona!
enumeration. Imputation
based on enumerator
observation or data reported
by respondents having similar
agricultural characteristics.
CV’s range from 1% to 2%
for national estimates of
major crop acreage and
livestock inventories and from
3% to 8% for corresponding
State estimates.
Minimized through rigid quality
controls on the collection
process and careful review of
all reported data.
U.S. Department of
Agriculture, SRS, S c o p e a n d
M e th o d s o f th e S ta tis tic a l
R e p o rtin g S e rv ic e ,
Miscellaneous Publication No.
1308, July 1975.
Mall or personal Interviews
used for initial data collection.
Mail nonrespondent followup
by phone and personal
interviews. Imputation based
on average of respondents.
Estimated CV for number of
hired farm workers is about
3%. See above for CV's of
other national and State
estimates.
In addition to above,
replicated sampling
procedures used to monitor
effects of changes In survey
procedures.
See above.
Enumerators count and
measure plant characteristics
in sample fields. Production
measured from plots at
harvest. Harvest loss
measured from post harvest
gleanings.
CV’s for national estimates of
production are about 2% to
3%.
See above.
See above.
Survey data for employers
collected by questionnaire.
IRS business tax forms used
for establishments without
paid employees. Followup on
problems with questionnaire
responses. Within industry, by
State cross-classifications,
missing data imputed based
on relationships of known
responses to administrative
data.
Estimated CV of about 1% at
national level for estimated
totals of all construction and
about .5% for construction
subindustries.
Response rate 80% to 85%
for most items. Computer
scan used to identify
Incomplete questionnaires for
review.
U.S. Bureau of the Census,
C e n s u s o f C o n s tru c tio n
in d u s trie s , 1 9 7 7 , vol. 1,
Industry and Geographic Area
Statistics.