Table 1

Characteristics of the sample of Ontario ICI construction businesses by unionisation status

	Unionised (n=5267)		Non-unionised (n 55 158)		P value
	n	%	n	%	P value
Annual full-time equivalent employees					<0.0001
≤1	894	17.0	32 646	59.2
2–4	1034	19.6	13 636	24.7
5–19	1640	31.1	7134	12.9
20–49	823	15.6	1283	2.3
50+	876	16.6	459	0.8
Complexity (no of businesses in company)					<0.0001
1	3061	58.1	47 035	85.3
2	1196	22.7	5977	10.8
3	437	8.3	1353	2.5
4	263	5.0	425	0.8
5 or more	310	5.9	368	0.7
Geographical region (first letter of postal code)					<0.0001
K	710	13.5	8059	14.6
L	2197	41.7	23 282	42.2
M	673	12.8	7690	13.9
N	862	16.4	11 333	20.6
P	485	9.2	3173	5.8
Other	340	6.5	1621	2.9

P values based on Pearson’s χ² test for differences. The distribution of industrial subsector (classification unit) for unionised and non-unionised businesses is presented in online supplemental appendix A.
ICI, industrial, commercial and institutional.