Methods, apparatus, systems and articles of manufacture to credit media segments shared among multiple media assets are disclosed. Example methods disclosed herein include comparing a sequence of monitored media signatures with a library of reference signatures to determine a signature match, the monitored media signatures representative of a monitored media presentation. Disclosed example methods also include determining duration and offset of the signature match, the offset to represent a position of the signature match relative to a start of a reference media asset associated with the signature match. Disclosed example methods further include crediting a segment of the monitored media presentation represented by the signature match to an identifier of a class of media assets including the reference media asset in response to a determination that (i) the duration of the signature match does not exceed a first threshold and (ii) the offset does not exceed a second threshold.