This sudden jump is an artifact of incorporating the 2010 census results. See here.
Labor Force Statistics from the Current Population Survey How the Government Measures Unemployment
If the Obama critics are correct I suggest that this is how the Current Population Survey (CPS) -- a.k.a., BLS household survey, I believe -- be used to get the results wanted. -- to wit, how the BLS could change the interpretation of the answers to the survey questions and get the results that may have been demanded by the Administration. This is not the census that I am talking about it is the monthly BLS household survey.
Below are some quotes from my link above.
"To know about unemployment—the extent and nature of the problem—requires information . . . After these statistics are obtained, they have to be interpreted properly so they can be used . . . ."
As I understand it, there are not questions like, "Are you marginally attached to the labor force?"
"Based on information collected in the survey and definitions programmed into the computer, individuals are then classified as employed, unemployed, or not in the labor force."
"definitions programmed into the computer" - I doubt that that has changed since the days of the IBM7080; to wit, tables. The computer consults tables to interpret a response to a question. The tables are there to be modified between runs in response to users' needs. So this month a particular response can have a different interpretation from last month.
There is absolutely nothing wrong with using tables. They are essential. But I suppose it's like the saying "Figures don't lie, but liars figure."
I recall the recovery from the 2001 recession. The same kind of arguments raged. But of course that was real recovery though somewhat anemic historically. IMO.
The household survey has nothing to do with actual hiring. That is documented from real W-2 and such data provided by the establishment survey of 400,000 businesses.