What is Systematic Short-term working, exactly?

[usrbin]

This is taken from Revenue leaflet IT1 (or at least the online version of it):

Tax Relief Available to Systematic Short-time Workers

The exemption from income tax for Unemployment Benefit paid to systematic short-time workers is available until the end of December 2006.

I'd be very grateful if somebody could define "Systematic short-term workers" for me... (Oasis and Revenue.ie have nothing)

 

[DrMoriarty]

systematic short-time workers

It's what they used to call 'permanent part-time' — they tidied up the definition a few years ago, when SST workers became entitled to a range of job protection/pension/PRSI benefits that previously applied only to those in 'full-time' employment.