TABLE 3.

Fit indices for the models (N = 314).

Model	χ 2	df	GFI	CFI	NFI	TLI	RMSEA	Model comparisons	Δχ 2	Δ df
Step 1: testing the relations between need satisfaction and motivation
M1stability	154.50	57	0.94	0.95	0.93	0.92	0.074
M1causality	130.53	53	0.94	0.96	0.94	0.93	0.068	M1stability-M1causality	23.97**	4
M1reversed	148.48	53	0.94	0.95	0.93	0.92	0.076	M1stability-M1reversed	6.02	4
M1reciprocal	126.54	49	0.95	0.96	0.94	0.93	0.071	M1stability-M1reciprocal	27.96**	8
M1final	133.65	54	0.94	0.96	0.94	0.93	0.069	M1causality-M1reciprocal	3.99	4
								M1reversed-M1reciprocal	21.94**	4
Step 2: testing the relations between motivation and heavy work investment
M2stability	233.84	75	0.92	0.96	0.94	0.93	0.082
M2causality	209.63	70	0.93	0.96	0.94	0.93	0.080	M2stability-M2causality	24.21**	5
M2reversed	176.27	70	0.94	0.97	0.95	0.95	0.070	M2stability-M2reversed	57.57**	5
M2reciprocal	167.75	65	0.94	0.97	0.95	0.95	0.071	M2stability-M2reciprocal	66.09**	10
M2final	179.97	71	0.94	0.97	0.95	0.95	0.070	M2causality-M2reciprocal	41.88**	5
								M2reversed-M2reciprocal	8.52	5