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. Author manuscript; available in PMC: 2015 Sep 3.
Published in final edited form as: Epidemiol Methods. 2013 Sep;2(1):85–93. doi: 10.1515/em-2013-0007

Table 2.

Summary statistics of the exposure–response parameter estimates for each scenario with exposure intensity distribution 2

True
hazard
ratio
Match ~30 cases per cohort
~100 cases per cohort
Na Meanb Empirical
standard
errorc
Estimated
standard
errord
Relative
efficiencye
(%)
Na Meanb Empirical
standard
errorc
Estimated
standard
errord
Relative
efficiencye
(%)
1 1:01 10,000 1.0000 2.84E–03 2.62E–03 36.9 3,000 1.0000 1.42E–03 1.40E–03 44.7
1:05 10,000 0.9999 1.95E–03 1.89E–03 78.5 3,000 1.0000 1.06E–03 1.00E–03 80.1
1:10 10,000 0.9998 1.84E–03 1.80E–03 88.3 3,000 1.0000 1.01E–03 1.00E–03 89.4
1:15 10,000 0.9998 1.80E–03 1.76E–03 92.1 3,000 1.0000 9.96E–04 9.96E–04 91.2
1:20 10,000 0.9998 1.78E–03 1.75E–03 93.9 3,000 1.0000 9.80E–04 9.87E–04 94.2
Full 10,000 0.9998 1.73E–03 1.70E–03 3,000 1.0000 9.51E–04 9.63E–04
1.005 1:01 9,999 1.0058 4.00E–03 3.09E–03 11.3 3,000 1.0052 1.50E–03 1.40E–03 20.8
1:05 10,000 1.0051 1.87E–03 1.79E–03 52.1 3,000 1.0050 9.12E–04 9.04E–04 56.4
1:10 10,000 1.0051 1.64E–03 1.59E–03 67.4 3,000 1.0050 8.14E–04 8.06E–04 70.8
1:15 10,000 1.0050 1.57E–03 1.50E–03 74.0 3,000 1.0050 7.74E–04 7.68E–04 78.4
1:20 10,000 1.0050 1.51E–03 1.46E–03 80.1 3,000 1.0050 7.51E–04 7.47E–04 83.1
Full 10,000 1.0049 1.35E–03 1.31E–03 3,000 1.0049 6.85E–04 6.79E–04
1.015 1:01 7,911 1.0206 2.20E–02 1.51E–02 0.3 2,992 1.017 6.62E–03 4.50E–03 1.0
1:05 9,897 1.0175 1.09E–02 5.51E–03 1.3 3,000 1.0154 2.07E–03 1.90E–03 10.4
1:10 9,987 1.0164 7.74E–03 3.51E–03 2.5 3,000 1.0153 1.55E–03 1.40E–03 18.5
1:15 9,996 1.0159 3.82E–03 2.79E–03 10.3 3,000 1.0152 1.37E–03 1.30E–03 23.7
1:20 9,996 1.0157 3.24E–03 2.48E–03 14.3 3,000 1.0152 1.23E–03 1.20E–03 29.4
Full 10,000 1.0152 1.22E–03 1.20E–03 3,000 1.0150 6.68E–04 6.92E–04

Notes:

a

N is the number of parameter estimates with corresponding standard error less than 1 as calculated by the PHREG procedure.

b

Mean is the exponential of the mean of the estimated log hazard ratios.

c

Empirical standard error is the sample standard deviation of the estimated log hazard ratios.

d

Estimated standard error is the mean of the estimated standard errors.

e

Relative efficiency of 1:m sampling was estimated by dividing the empirical variance obtained from the full risk-set analyses by the empirical variance obtained from the m-sampled risk-set analyses.