"Massages" makes it sound like the change the measures on the fly which is not the case. See my other comment about counting those not working vs. those not looking for work.
See for example this discussion of discrepancies between the BLS unemployment rate and the Gallup Poll unemployment rate (since 2010):
http://unemploymentdata.com/unemployment/is-the-government-f...
It is difficult to know if in practice the household surveys are done the same way each time and also what seasonal and "one-time" adjustments may be occurring either during the first measurement or subsequent corrections.
As the discrepancies between the BLS and Gallup numbers indicate, there is evidence of shorter term massaging not captured in the major redefinitions, such as excluding "discouraged workers" who want a job but supposedly have not looked for one recently, in the 1994 revisions to the unemployment measures.