Table 2.

Model parameters for the screening numbers per week in a multivariable generalized mixed-effects model (Poisson family with logarithmic link function)

Predictor	β coefficient*	exp (β)*	95% interval for exp(β)*	p value
Revision of inclusion criteria	0.186	1.204	(0.881–1.647)	0.243
Increase of travel expenses reimbursement	0.149	1.161	(0.859–1.570)	0.331
Investigator teleconferences	0.382	1.466	(1.018–2.112)	0.0398
Investigator meetings	−0.084	0.919	(0.705–1.199)	0.534
Core partner site	0.379	1.460	(0.254–8.392)	0.671
Reaching 80% of site recruitment target	−0.357	0.699	(0.542–0.903)	< 0.001
Public holidays	−0.763	0.466	(0.367–0.591)	< 0.001
Week	−0.006	0.994	(0.986–1.003)	0.202
Intercept	−4.19	0.015	(0.005–0.045)

* adjusted values. No evidence for overdispersion was found (dispersion parameter: 1.0098, p = 0.3820 [19]). Only a shared fixed intercept is added when the site is inactive (β₀ = − 4.19, exp.(β₀) = 0.015, 95% CI [0.005–0.045]). Random intercepts α for active clinical sites ranged from 3.42 to 4.35