Table 8. Evaluation of 1990 Final County Estimates: Errors by Method Combination and Use of Single Method

Source:  U.S. Bureau of the Census
Internet Release date:  June 20, 1997

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                    |       |          |                                MEASURES OF DIFFERENCE
                    |       |          |--------------------------------------------------------------------------------------------- 
                    | Number|   Number |          Mean |          Mean |   Weighted | Root Mean | Index of |       50th |
                    |     of|       of |     Algebraic |      Absolute | Mean Abso- |    Square | Dissimi- | Percentile |       90th
METHOD(S)           | States| Counties | Percent Error | Percent Error | lute Error |     Error |   larity |   (Median) | Percentile
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ADREC Only                 2       234             1.7             3.7          2.8         4.9        1.3          2.8          8.3
ADREC & Comp II            3       315             0.0             4.4          2.8         6.2        1.3          3.2          9.6
ADREC & Ratio-Corr.       32      2138             2.2             3.5          2.2         4.7        1.0          2.7          7.0
Ratio-Corr. &
    Comp II                1        25            -4.7             7.2          4.4        10.1        1.6          5.1         15.7
ADREC, Ratio-Corr.,
     & Comp II             9       279             0.9             3.3          2.2         4.4        1.1          2.6          6.6
ADREC, Ratio-Corr.,
     & Other               3       149             1.8             3.7          2.0         5.1        0.9          2.2          9.4
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                                           SINGLE METHODS COMPARED WITH STATES WITHOUT THE METHOD
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ADREC                     49      3115             1.8             3.6          2.2         4.9        1.1          2.7          7.3
  without                  1        25            -4.7             7.2          4.4        10.1        1.6          5.1         15.7

Ratio-Correlation         45      2591             2.0             3.5          2.2         4.8        1.1          2.7          7.1
  without                  5       549             0.8             4.1          2.8         5.7        1.3          3.0          9.0

Component II              13       619             0.2             4.0          2.5         5.7        1.2          3.0          8.6
  without                 37      2521             2.1             3.5          2.2         4.8        1.1          2.7          7.2
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