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. Author manuscript; available in PMC: 2013 Nov 30.
Published in final edited form as: Stat Med. 2012 Apr 25;31(27):3320–3327. doi: 10.1002/sim.5347

Table 1.

Results assuming environmental exposure is uncorrelated with calendar time.

Model Time Scale Controls Abs.Bias MSE Coverage Power
HR for 10-unit change in P = 1.1
T1 Time on study agei+agei2+P(t) 0.0095 0.00026 0.94 0.18
T2 Time on study agei+agei2+cy(t)+P(t) 0.0095 0.00026 0.94 0.17
A1 Attained age birth.cohorti +P(a) 0.0095 0.00026 0.93 0.16
A2 Attained age birth.cohorti + cy(a) +P(a) 0.0094 0.00026 0.93 0.16
C1 Calendar time agei+agei2+P(cy) 0.0092 0.00025 0.94 0.17
HR for 10-unit change in P = 1.2
Tl Time on study agei+agei2+P(t) 0.0087 0.00024 0.97 0.32
T2 Time on study agei+agei2+cy(t)+P(t) 0.0087 0.00024 0.97 0.32
A1 Attained age birth.cohorti +P(a) 0.0083 0.00023 0.96 0.33
A2 Attained age birth.cohorti + cy(a) +P(a) 0.0084 0.00024 0.96 0.30
C1 Calendar time agei+agei2+P(cy) 0.0088 0.00024 0.96 0.33
HR for 10-unit change in P = 1.3
T1 Time on study agei+agei2+P(t) 0.0085 0.00023 0.94 0.67
T2 Time on study agei+agei2+cy(t)+P(t) 0.0085 0.00023 0.95 0.67
A1 Attained age birth.cohorti +P(a) 0.0086 0.00023 0.94 0.70
A2 Attained age birth.cohorti + cy(a) +P(a) 0.0087 0.00024 0.95 0.65
C1 Calendar time agei+agei2+P(cy) 0.0088 0.00023 0.94 0.67
HR for 10-unit change in P = 1.4
T1 Time on study agei+agei2+P(t) 0.0084 0.00024 0.96 0.90
T2 Time on study agei+agei2+cy(t)+P(t) 0.0084 0.00024 0.96 0.91
A1 Attained age birth.cohorti +P(a) 0.0085 0.00024 0.94 0.90
A2 Attained age birth.cohorti + cy(a) +P(a) 0.0087 0.00024 0.94 0.90
C1 Calendar time agei+agei2+P(cy) 0.0088 0.00024 0.93 0.90
HR for 10-unit change in P = 2
T1 Time on study agei+agei2+P(t) 0.0085 0.00023 0.94 1.00
T2 Time on study agei+agei2+cy(t)+P(t) 0.0087 0.00024 0.95 1.00
A1 Attained age birth.cohorti +P(a) 0.0089 0.00024 0.93 1.00
A2 Attained age birth.cohorti + cy(a) +P(a) 0.0088 0.00024 0.94 1.00
C1 Calendar time agei+agei2+P(cy) 0.0084 0.00024 0.93 1.00

Notes: P(m) and cy(m) denote that the time-varying values of the environmental exposure and calendar year variables, respectively, are selected relative to the time scale over which the model is being fit. MSE = Mean Squared Error.