Together with Shlomo Argamon and Jonathan Schler, he has shown that statistical analysis of word usage in a document can be used to determine an author's gender, age, native language, and personality type.

Together with Shlomo Engelson Argamon and Jonathan Schler, he has shown that statistical analysis of word usage in a document can be used to determine an author's gender, age, native language and personality type.

He has applied his authorship attribution methods to proving that the 19th century Baghdadi rabbi known as Ben Ish Chai was the actual author of a book for which he did not take credit.

[15] Koppel also showed that the Harson collection (Hebrew: הגניזה החרסונית), a trove of letters attributed to early Hassidic masters were in fact all forgeries.

[17] Koppel has been active in efforts to draft a formal constitution for the State of Israel, intended to replace the quasi-constitutional system of Basic Laws from which the government derives its powers.

He also wrote legislation passed by the Knesset in February 2011 that required full disclosure by NGOs regarding funding received from foreign governments.