Computers and human readers can identify Shakespeare’s writing through “plus-words”—such as “gentle”, “answer”, “beseech”, “tonight”—which he uses frequently. This method becomes less accurate, though, when writers ape one another’s style as they often did in Elizabethan theatre-land. Early modern playwrights were a close-knit bunch and 16th-century audiences do not appear to have placed a high premium on novelty. “Tamburlaine”, Christopher Marlowe’s wildly popular play, spawned so many knock-off sequels and serials that Ben Jonson, a fellow playwright, felt compelled to lament the endless “Tamerlanes and Tamer-chams of the late age”. Shakespeare was as guilty of this as anyone. In “The Jew of Malta” (1589), Marlowe’s Barabas spies his daughter Abigail on a balcony:

“But stay! What star shines yonder in the east?

The lodestar of my life, if Abigail!”

If the lines sound familiar, it’s because Shakespeare’s Romeo echoed them ten years later:

“But soft! What light through yonder window breaks?

It is the East, and Juliet is the sun!”

With this mutual influence muddying the picture, how can computers tell the difference between Marlowe, Shakespeare, and Marlowe and Shakespeare drawing on one another? According to the editors of the “New Oxford”, the answer lies in “function words”. These are words like “to” or “a” that supply the grammatical mechanics of a sentence. The theory goes that all writers unconsciously use these words in distinctive ways. Shakespeare, for example, often put “and” next to “with”—Claudius marries Gertrude “With mirth in funeral and with dirge in marriage”, Old Hamlet’s ghost “Appears before them, and with solemn march / Goes slow and stately”. As a result, function words supposedly betray a writer’s identity, even when they’re trying to write like someone else. By analysing how a writer uses function words, computers can ostensibly identify their unique linguistic fingerprint.

According to Gabriel Egan, one of the editors of the “New Oxford Shakespeare”, attribution models are becoming ever more accurate, partly because “computational people are increasingly turning to linguistic problems, because they are among the hardest problems that we can put computers to work on.” Where does this leave Bernard Nightingale’s fuming insistence that “you can’t stick Byron’s head in your laptop”? For now, he’s probably right. On a control test, even the advanced models used by the “New Oxford” sometimes misattributed works whose authorship we know for sure. For now, statistical analysis will remain one of many editorial tools. Nevertheless, it represents a strain of academic objectivity, rarely found in the field of Shakespeare studies.