I'm trying to understand how representing chunks works by facing this question :
The IOB format categorizes tagged tokens as I , O , and B . Why are three tags necessary? What problem would be caused if we used I and O tags exclusively? ch7, Extracting Information from Text,
Natural Language Understanding with Python,S. Bird, E. Klein, and E. Loper
In IOB scheme,
Each token is tagged with one of three special chunk tags, I (inside), O (outside), or B (begin). A token is tagged as B if it marks the beginning of a chunk. Subsequent tokens within the chunk are tagged I . All other tokens are tagged O .
I don't understand why would it be an issue to only have inside and outside tags, we would still have chunks which is the main purpose of this method, no ?