Mixing modes in a population-based interview survey: comparison of a sequential and a concurrent mixed-mode design for public health research

Table 7 Model calculation for a cost analysis in concurrent and sequential mixed-mode designs (number of cases: 20,000; sequential mixed-mode design response rate: 20.0%)^a

	Concurrent mixed-mode design					Sequential mixed-mode design
	Numberof mailings	Cost factors				Numberof mailings	Cost factors
	Numberof mailings	Small letter	Large letter	Printed questionnaire	Data entry	Numberof mailings	Small letter	Large letter	Printed questionnaire	Data entry
1st contact	91 419		91 419	91 419		100 000	100 000
2nd contact	75 802	75 802				89 018		89 018	89 018
3rd contact	67 666	67 666				79 673	79 673
Total letters	234 887	143 468	91 419	91 419		268 690	179 673	89 018	89 018
Valid questionnaires SAQ-Paper	15 908				15 908	9531				9531
Valid questionnaires SAQ-Web	4092				0	10 469				0
Valid questionnaires	20 000					20 000
Cost analysis
Costs per unit		0.70 €	2.20 €	3.00 €	9 min		0.70 €	2.20 €	3.00 €	9 min
Postage and printing costs in €		100 427.74	201 122.11	274 257.43			125 770.83	195 839.29	267 053.57
Postage for received questionnaires in €			34 996.70					20 967.51
Total postage and printing costs in €				610 803.97					609 631.20
Total costs in working minutes					143 168					85 776
Total postage and printing costs per valid questionnaire in €				30.54					30.48
Total working time needed per valid questionnaire (min.)					7.2					4.3
Total costs for 20 000 valid questionnaires in working hours (working weeks), rounded up					2400 (62)					1450 (37)
Costs for working time in € (per pay scale of public service)^b					59 182.82					35 318.18
Total postage and printing costs for 20 000 valid questionnaires (in €)				610 803.97					609 631.20
Total costs for 20 000 valid questionnaires (in €)					669 985.79					644 949.38

^aExcluding overhead costs and working time for supervision, data cleaning, and homogenization
^bCalculated with German TVöD 4 (payment 42 000 €/year including social insurance), 44 weeks crude data entry per year

ISSN: 2049-3258