Table 4.

Difficulties in clinical research by study characteristics^a

	Study characteristics
	Privatebsponsorship	Public sponsorship		Multi center	Single center		Otherc	Clinicald
Difficulties with:	%	%	p	%	%	p	%	%	p
Literature review (get relevant articles, read, synthesize)	2.4	6.9	0.19	3.1	7.9	0.078	7.2	4.9	0.39
Research question (formulation of a main research question and/or hypothesis)	1.2	13.1	0.001	3.2	15.0	<0.001	15.1	5.9	0.004
Study design (identification of the study design, variables, instruments, analysis, including calculation of the sample size)	2.4	25.8	<0.001	8.2	29.1	<0.001	23.3	18.0	0.21
Approval by the Research Ethics Committee	12.2	17.9	0.25	11.9	20.3	0.038	12.8	20.4	0.056
Getting funding	3.7	23.9	<0.001	13.8	23.1	0.026	19.0	19.5	1.00
Approval by the safety agencies (Swiss Agency for Therapeutic Products, etc.)	17.3	8.3	0.023	14.6	7.0	0.024	3.9	15.7	<0.001
Patients enrollment	51.3	41.5	0.13	48.1	42.5	0.30	37.1	51.5	0.005
Data collection	19.5	28.9	0.12	22.0	30.0	0.10	26.1	27.2	0.82
Collaboration with caregivers for patient enrollment	18.3	22.1	0.54	20.1	21.8	0.80	19.4	22.5	0.53
Recruitment of competent persons to conduct the study	12.2	22.0	0.059	16.4	22.9	0.12	16.7	23.3	0.13
Data management	6.1	20.4	0.002	10.1	21.8	0.002	19.6	14.6	0.22
Data analysis (statistical or other) and results interpretation	3.7	26.7	<0.001	10.8	29.3	<0.001	23.5	20.1	0.46
Writing a manuscript for a scientific publication	1.2	23.8	<0.001	8.9	25.6	<0.001	20.9	16.7	0.36
Publication in a peer-reviewed journal	4.9	25.5	<0.001	14.6	24.8	0.020	21.1	20.0	0.80
Other(s) difficulty(ies)	3.7	5.8	0.58	5.0	5.3	1.00	8.9	1.9	0.002

^aSelected from the multivariable model (Table 3). P-values come from the Fisher’s exact test

^bIndustry or foundation

^cHealth/illness, public health, methodology, etc

^dIntervention or diagnosis or prognosis