"fit index" is a correct and usable part of a sentence in written English.
You could use it to describe a numerical measure of the fitness of an individual, such as "The patient's fit index was high."
Parsimonious normed fit index.
adjusted goodness of fit index.
Normed Fit Index (Bentler-Bonnet).
The Goodness of Fit Index (GFI) equals 0.91, Adjusted Goodness of Fit Index (AGFI) equals 0.76 and Parsimony Goodness of Fit Index (PGFI) equals 0.35.
The hypothesized model fit the data was also excellent, with X2 = 4.42 X2/df = 5, Goodness of Fit Index (GFI): 0.97; Adjusted Goodness of Fit Index (AGFI): 0.84; Comparative Fit Index (CFI): 0.96, and Normal Fit Index (NFI): 0.96.
The hypothesized model fit the data was excellent, with X2 = 3.14 X2/df = 5, Goodness of Fit Index (GFI): 0.96; Adjusted Goodness of Fit Index (AGFI): 0.91; Comparative Fit Index (CFI): 0.97, and Normal Fit Index (NFI): 0.97.
According to Cheung & Rensvold (2002), other important indexes to compare the target model with the null model are relative fit index (RFI), comparative fit index (CFI), normal fit index (NFI), and incremental fit index (IFI).
