Table 8.

Proportion (%) of attributed and missing data in dates used to calculate elapsed times (Appendix A).

	All patients		Breast cancer		Lung cancer		Colorectal cancer
	(n = 307)		(n = 107)		(n = 91)		(n = 109)
	Attributed data∗	Missing data	Attributed data∗	Missing data	Attributed data∗	Missing data	Attributed data∗	Missing data
Date of first symptoms	52	13	52	17	43	12	58	11
Date of scheduling appointment	39	24	38	23	34	26	45	22
Date of start of investigation	37	11	28	12	32	9	50	13
Date of diagnosis	341	0	202	0	333	0	484	0

^∗Patients who were unable to provide specific dates were asked to indicate the month and year of the event and to specify whether the event occurred at the beginning, middle, or end of the month; the date corresponding to the mid-point of that period was then attributed to the event. Residual missing data for date of diagnosis were estimated from the dates of diagnosis entered in the oncology clinics' cancer registries. However, since self-reported dates of diagnosis usually differed from registries' dates of diagnosis, we replaced missing data in questionnaire by the data of the registries, adjusted by the mean difference between the dates of diagnosis entered in the registries and the dates indicated by responding patients, by cancer site.

¹This proportion includes 26% from partial data provided by patients and 8% from the cancer registries.

²This proportion includes 17% from partial data provided by patients and 3% from the cancer registries.

³This proportion includes 23% from partial data provided by patients and 10% from the cancer registries.

⁴This proportion includes 36% from partial data provided by patients and 12% from the cancer registries.