Table 3. Item response theory analysis for specific and social fears in the total sample (n=2,512).

	Confirmatory factor analysis (bifactor model, general factor)					Item response theory (unidimensional model)
		Category thresholds					Discrimination
	Factor loadings (λ)	A little	A lot	Location (mean)	Location rank	Slope (a)	A little (b1)	A lot (b2)	Item location (mean b)	Location rank
Specific fears
Animals	0.221	-0.126	0.996	0.435	1	0.942	-0.254	2.048	0.897	2
Natural environments
Storms, thunder, heights	0.262	0.103	1.133	0.618	4	1.286	0.168	1.885	1.0265	4
Dark	0.259	0.025	0.978	0.502	2	1.12	0.033	1.766	0.8995	3
Blood, injection, injury
Blood, injection, injury	0.34	0.029	1.017	0.523	3	1.291	0.044	1.677	0.8605	1
Dentists, doctors	0.403	0.535	1.392	0.964	6	1.218	0.904	2.426	1.665	6
Situational
Modes of transport	0.402	1.356	2.081	1.719	15	1.444	2.116	3.382	2.749	13
Enclosed spaces	0.37	1.109	1.849	1.479	12	1.52	1.666	2.872	2.269	12
Toilets	0.356	1.300	2.024	1.662	13	1.316	2.153	3.493	2.823	14
Other fears
Monsters etc.	0.322	0.533	1.384	0.959	5	1.414	0.823	2.191	1.507	5
Vomiting, choking, diseases	0.388	0.770	1.610	1.190	8	1.414	1.196	2.575	1.8855	9
Loud noises	0.344	0.886	1.643	1.265	9	1.584	1.299	2.469	1.884	8
People who look unusual	0.351	1.379	2.024	1.702	14	1.357	2.243	3.417	2.83	15
Social fears
Not restricted to performance
Meeting new people	0.783	1.632	2.449	2.041	18	1.409	2.626	4.165	3.3955	18
Meeting a lot of people	0.89	1.524	2.259	1.892	16	1.644	2.234	3.431	2.8325	16
Eating in front of others	0.804	1.506	2.449	1.978	17	1.555	2.278	3.917	3.0975	17
Performance only
Speaking in class	0.747	0.806	1.811	1.309	10	1.399	1.262	2.95	2.106	10
Reading in front of others	0.727	0.566	1.551	1.059	7	1.33	0.913	2.571	1.742	7
Writing in front of others	0.739	1.041	1.871	1.456	11	1.504	1.576	2.921	2.2485	11

All items loaded significantly on their respective latent factors (p < 0.0001).

Threshold limits: 0.78 in confirmatory factor analysis and 1.53 in item response theory.

Bold indicates problem indicators.