Hi,
WOCF = Worst Observation Carried Forward
LOCF = Last Observations Carried Forward
BOCF = Best Observation Carried Forward
For continuous data it can be important to have values at each timepoint. Each of these appies a rule for missing data that a previous result is put where the missing data element is, so for instance if visit 2 is missing, but visit 1 is present, and LOCF is specified then the visit 1 result is put into visit 2 also.