On the writing credits of a song…

How is it decided whose name goes first?

There is no set rule. Traditionally, the composer got first billing (e.g., Rodgers and Hart/Hammerstein, George and Ira Gershwin, Warren and Dubinm, Kander and Ebb, Webber and Rice), though there are exceptions (Lerner and Lowe).

When there are two songwriters, they usually pick an order and stick with it (Lennon/McCartney, Adler and Ross, Jagger/Richards). Sometimes the songs are collaborations, sometimes not.

Occasionally, someone gets tired of sharing credit, or insists on top billing. It’s mostly an ego thing, though – both songwriters get equal money for the song.

There are a number of cases of DJ’s most notabley Alan Freed getting songwriting credit and the resulting royalties as “payola” in exchange for hyping and playing the song on their show.

Also Elvis got song writing credit for a few of his songs, Love Me Tender being an example, even though he never actually wrote any of them.

just a guess - alphabetical order? (when there are two songwriters) all the ones that immediately spring to mind are in alphabetical order.

eg lennon/mccartney

it’s probably often used by bands to establish an order without giving special preference to anyone.