Type: 			test statistic
WDH symbol: 		b-fix
Primary correlate level: 	metric
Secondary correlate level: nonmetric
Happiness level: 	metric
Theoretical range:	unlimited
Meaning:
Variant of  usual (non-standardized) regression coefficient (b), which controls for the secondary variables, by focusing on differences from a fixed level, such as the mean in a category. Aims to reduce  the residual variance and to improve the precision of the regression coefficient. 
References:
Wikipedia: http://en.wikipedia.org/wiki/Fixed_effects_model 
Non-technical text: http://www.jblumenstock.com/files/courses/econ174/FEModels.pdf