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Table 1 Variables included in the simulation study, generating models, and notation

From: Evaluation of biases present in the cohort multiple randomised controlled trial design: a simulation study

Variable description

Generating models and notation

Number of simulated data sets

N sim

Sample size each data set

N obs

Treatment allocated

Z i  = 0/1 for standard of care/intervention

Treatment received

X i  = 0/1 for standard of care/intervention

Baseline hazard function for time until CVD event

\( {h}_0\left({t}_c\right)={\gamma}_c{\lambda}_c^{\gamma_c}{t}_c^{\gamma_c-1},\kern0.5em {\lambda}_c=36,\kern0.62em {\gamma}_c=1.2 \)

Baseline hazard function for time mortality

\( {h}_0\left({t}_m\right)={\gamma}_m{\lambda}_m^{\gamma_m},\kern0.5em {\lambda}_m=55,\kern0.5em {\gamma}_c=1.2 \)

Individual random effects

ε i  ~ N(0, σ 2), σ = 0.7

Intervention effect

β = − 0.32

Individual hazard function for time until CVD event

\( h\left({t}_{i c}\right) = {h}_0\left({t}_c\right)\ {e}^{\left(\beta {X}_i+{\varepsilon}_i\right)} \)

Individual hazard function for time until mortality

\( h\ \left({t}_{i m}\right)={h}_0\left({t}_m\right)\ {e}^{\left({\varepsilon}_i\right)} \)

Probability of a patient refusing intervention if offered and average patient refusal

\( \begin{array}{l}{p}_i, p={\varSigma}_i{p}_i/{N}_{obs}\\ {}\end{array} \)

Probability of clinician refusing to offer the intervention to the patient and average clinician refusal

\( \begin{array}{l}{q}_i, q={\varSigma}_i{q}_i/{N}_{obs}\\ {}\end{array} \)

Trial follow-up time in years

T max = 3

Censoring indicator

C i  = I(T ic  ≥ min(T im , T max  ))

Observed outcome

Y i  = min(T ic , T im , T max )

Observed trial data

{Y i , C i , Z i , X i }