Pete Mason, the driving force behind the PhanArt project has submitted the following essay on predicting a bands songs in the live setting
At any concert, the music is the ultimate reason for attending the event, yet knowing the name of the songs certainly adds to the evenings fun. Being able to predict to see into the immediate future, to call out the name of a song as it develops out of a jam, or simply out of nothingness is an impressive feat, and a source of pleasure for fans of Phish, Widespread Panic, moe., The Grateful Dead and The Disco Biscuits and many other band. Correctly predicting the next song often shows experience, foresight and a finely tuned ear.

How does one call the song? Fans will or have invariably used any or all of these methods, some of the most commonplace staples in song-prediction over the years (Beyond asking those around you after the song has been playing for a few notes, What is this song or What is this still?): Racing your friends to see who can come up with the song title firstKeeping that call to yourself, so that the accuracy or lack thereof is kept withinCalling out song titles left and right, hoping you hit on at least one accurate oneGiving a one shot guess and letting it be for the night Picking one song and calling it at the time you feel most right, and seeing what happens from there. You may well be wrong much of the time, but in those fleeting moments when the song hits, you become god-like to those around you.
There are various ways in when concert-goers call out the music they are soon to hear:
Calling the opener: Quite possibly the #1 musical pastime event prior to a concert that fans of jambands will partake in, anticipating the elusive show opener. Call it correctly and you are locked into that shows collective memory among your circle of friends. Call it incorrectly, and you are forgiven, because really, anything can be played to open a show. How many fans correctly guessed that Phish would finish 12/30/03s Wilson as the opener for 12/31/03, or that at any given gig, the Disco Biscuits will complete a version of a song from a prior night? On the other end of the spectrum, many Phish fans who went to Big Cypress suspected the group might play Water in the Sky to open this historic millennial show, since the line filter out the Everglades may have been one of the most apt openers in the bands blooming history.
_Calling the next song (jammed into from a previous number): _ This takes a degree of knowledge about the bands material, taking into account numerous hours listening to jam after jam and hearing the idiosyncrasies that make one songs jam stand out from others. Have you listened to multiple versions of And the Ladies Were the Rest of the Night? Do you know how it morphs out of one song and into itself? Then you might be able to call this song out with little difficulty. Somewhere in there, it might even feel like you channeled the band to play the song.
_Calling the next song (with no song or jam preceding it): _ This is nothing but pure luck usually. You can step back and think Hmm, what frequent song have they not played in the last couple nights? What would they play here (i.e. mid set, end set)? What would be out of the blue? If you know any signals given between band members (see Umphreys McGee) to denote a possible next tune, or hear that elusive guitar chord that cues a memory bank of songs that start with that note, then you might just be able to pull this off.
_Recognizing the teases: _ Hearing the one second or full on blast of a tease of a song of indeterminate value to a given fan is a treat, and while easy to identify, you have to have the finely tuned ear to know when it is coming, when it ends, and of course, what the heck it was. You can enjoy the concert without noting these teases, but you know when you listen to it days or weeks or months later, you will hear it and say I totally missed that, but not feel as though the concert was a wash because of it.
Calling the encore: depending on the band in question, this can vary significantly. There are some bands that use a staple set of encores for each tour they undertake (Aint Life Grandcan be a WSP staple, Phish always has Tweezer Reprise, moe. had Raise a Glass for the Winter 2008 tour) and that makes them easy to call, but some bands such as Disco Biscuits and Umphreys McGee are so unpredictable, its better to not wonder and just prepare yourself to identify the song and get ready to get down. You can also take into account the previous nights encore, and come within a good deal of accuracy that nights encore, or at least have a 24-48 hour advance notice to those around you of the encore for the next show.
The method someone uses to call out the next song has some more consistency to it, but the style is the main factor. There is a degree of anxiety in trying to hear the opening notes to a song first, especially when it was coming in the jams between songs. Many times have I stood there and heard the next song slow-rolling out of one song, stroked my chin in hopes of remembering the tune, and got the name out just in time, only to find out I didnt know this band well enough, and was this close to the real song title.
The remark I know this song is heard by many and spoken by countless more, as a fans brain is wracked trying to remember how this da-duh-duh-dumdum-DA fits into their memory bank of songs by this band. The more shows you see, the better these predictions can get, and in time, you can know the next song coming up, smile gleefully to yourself and never lose a stride as you dance dance dance into the oblivion of your knowledge and the music set before you. It becomes something almost fun to do, like a musical word search you can point out the familiar, lose grasp of what it could be, and then arrive at Holy Shit, its __________. This often elicits a knowing nod from those around you who were listening while making this bands community more of a home than a stop on the road.
Predicting songs at concerts has become part of our collective consciousness, something we all think about, something we debate discuss and deride others over, but most importantly, it is something that is unique to the jamband scene more than any other – predicting songs is fun and shows true and reverent fandom for bands that make you think with both halves of the brain.