Difference between IOB and IOB2 format? I have to tag a dataset for NER. I came across conll2002/esp. What I understand so far, in IOB2 format if I want to tag 'Alex Larson is going to Los Angeles for a job interview with Candace Patrick' it'll be like:

Alex B-PER
Larson I-PER
is O
going O
to O
Los B-LOC
Angeles I-LOC
for O
a O
job O
interview O
with O
Candace B-PER
Patrick I-PER


Am I right? What about IOB format?
The difference is not related to the length of the named entities. Rather, it deals with how two adjacent named entities of the same type are labeled.

In IOB1 (IOB), B- is only used to separate two adjacent entities of the same type:

Today    O
Alice    I-PER
Bob      B-PER
and      O
I        O  # or I-PER if pronominals are being tagged
ate      O
lasagna  O


In IOB2, all entities begin with B-:

Today    O
Alice    B-PER
Bob      B-PER
and      O
I        O  # or B-PER if pronominals are being tagged
ate      O
lasagna  O


See Wikipedia