The Relationship Between The 1990 Census and ... - Census Bureau

went to category 340, “Emergency medical technicians (EMTs) and paramedics,” and 22.9 percent
went to category 365, “Medical assistants and other healthcare support occupations.” Note that this is
a good example of a 1990 category for which the 1990 double-coded sample provided a different
distribution of people than the census index provided of occupational titles. The index predicted a 60-
20-20 percent distribution of the 1990 Census category 106 to Census 2000 categories 311, 340, and
365, respectively. But the 1990 sample revealed that a much larger proportion of people (41.7 versus
20 percent) in this 1990 category described themselves as EMTs or paramedics instead of as physician
assistants, which put them in Census 2000 category 340 instead of 311.
When only one 2000 category appears for a 1990 category in Table 1 and 2, then that entire 1990 category
went into a single 2000 category. The conversion factor is 100 percent. Note, however, that the two
categories may not necessarily be exactly equivalent. In other words, even though an entire 1990 category
went into a single 2000 category, the reverse may not be true. For example, two 1990 categories could
merge into one 2000 category; in this example the 2000 category would be equivalent to the combination
of the two 1990 categories.
Example 3 (Table 1). 1990 Census industry category 011, “Agricultural production, livestock” went
entirely (100 percent) into Census 2000 category 018, “Animal production.” Note, however, that the
reverse is not true. Most of 2000 category 018 came from 1990 category 011, but some of it came
from 1990 category 030, “Agricultural services, n.e.c.,” and from category 032, “Fishing, hunting, and
trapping.”
Example 4 (Table 2). 1990 Census occupation category 003, “Legislators,” went entirely (100
percent) into Census 2000 category 003, “Legislators.” The 1990 and 2000 categories, in this
example, are truly equivalent: all of the 1990 category went to one 2000 category and the 2000
category came entirely from the one 1990 category. This, by the way, is the only category where the
code (003) is the same for both censuses.
To help analysts sort out those categories that are the most comparable from 1990 to 2000, the last
column in Tables 1 and 2 may show a code from 1 to 3 that designates the following levels:
1 = Directly comparable (conversion factor = 100 percent); 96 of the 236 1990 industry codes and
180 of the 501 1990 occupation codes got this score.
2 = Estimated to be 95-99.99 percent comparable; 46 industry and 82 occupation codes got this score.
3 = Estimated to be 90-94.99 percent comparable; 28 industry and 40 occupation codes got this score.
The code will appear on the lines that display the code combinations with conversion factors equal to 90
percent or higher.
Table 3 is very similar to Table 2, but the 501 occupation categories shown on the 1990 Census Equal
Employment Opportunity (EEO) File are distributed into only the 471 civilian occupation categories
shown on the Census 2000 EEO File and 5% PUMS (plus one more category for the unemployed who
were not classified by occupation). For Census 2000 the smallest of the 505 detailed civilian occupation
categories had to be aggregated into the 471 to avoid the possible disclosure of information about
individual respondents. The “smallest” categories are defined as those with fewer than 10,000 people
coded nationwide in 2000.
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