They count (I don't know how) the number of people in jobs. This has gone up, a lot in the last quarter. Reports on lunchtime news said we've just had one of the biggest ever drops in unemployment.
But they also count the number claiming JSA - this has also gone up a bit.
Other adults who don't fall into these categories are classed an economically inactive (which would include those living off redundancy payments).
I'm not sure what this means in terms of the overall picture (perhaps there will be more analysis on the evening news). But it suggests that: a) more jobs have been created, and b) more people are actively seeking work (whether through choice or change in benefit availability).
The numbers claiming JSA are only some of the out of work and looking for work people. eg if you have a partner who works you only get JSA for 6 months, then you are counted as a SAHP. It also doesn't count people on incapacity benefit and Employment Support allowance who are actively ooking for work, or young OAPs who would take a job if they could find one, or student who cant find jobs over the holidays.
there are loads of groups of people who 'slip through the net'.
meditrina - the number of people 'in work' was estimated based on a survey (yougov type thing) whereas the JSA claimants are the actual numbers.
"in employment" can mean a variety of things that are not full time, as sassy pointed out. It includes part time workers who want to work full time, it includes self employed who may not be making a wage, etc.