Tryouts
Up until the 1960s, almost all new musicals were taken on tour to work out any kinks before opening on Broadway. Just how much fun is it to take a new musical out on the road? A writer (sources differ as to who) once quipped that the worst he could wish on Hitler was that he be stuck out of town, working on a musical during its pre-Broadway tryout. Its amazing how many producers have ignored disapproval on the road. When the owner of Bloomingdales opened the ill-advised musical Allah Be Praised (1944) in Philadelphia, he called in play doctor Cy Howard (another version says it was it playwright George S. Kaufman), who urged him to "close it and keep the store open nights." Refusing to cut his losses, Bloomingdale brought the show to Broadway, where it quickly failed.

The original production of No, No Nanette toured for nearly two years, changing most of the score and libretto before it finally came to New York. As a rule, most shows toured for no more than a few weeks. Favorite tryout cities included New Haven, Boston, Philadelphia, Atlantic City and Baltimore. Today, any town with a respected regional company may become a tryout location.

Tryouts have often involved exhausting re-writes and revisions. After the authors sit up all night re-writing scenes and songs, the cast rehearses the changes and add them as soon as possible. This frequently entails rehearsing the new material in the morning, performing the old version at a matinee, and debuting the new material that evening! When Call Me Madam was previewing in Boston, the authors kept re-writing until it got on leading lady Ethel Merman's nerves. As she later told it –

They never stopped trying to add a joke, tidy up an exit, improve a punch line. I went along with the tinkering until the Thursday before our New York opening, when the show was supposed to be frozen -- meaning no more changes. Still they continued making a change here and there until I faced them down, saying, "Boys, as of right now, I am Miss Birdseye of 1950. I am frozen. Not a comma!"
– Merman – An Autobiography (New York: Simon & Schuster, 1978), p. 164.

In the "good old days," a show followed up its tryout tour by playing one or two previews in New York (for technical purposes) before all the critics attended the official opening night. For a hilarious, and only slightly exaggerated glimpse at what the traditional tryout process could be like, track down a video of the classic MGM musical The Bandwagon (1953). Writers Betty Comden and Adolph Green based the film on their actual experiences with egotistical directors, frazzled stars, sets the refused to work and backers that slithered into the night at the first sign of trouble. 

Previews
Since the 1970s, it has been too costly for most musicals to tour before opening in New York. Some shows now start with full-scale productions at one or more regional theatres. Other producers opt for four to six weeks of Broadway previews, charging full price to those adventurous enough to catch a work in progress. 

The downside of extended Broadway previews is that a new show is subjected to the merciless scrutiny of New York's theatrical community. Many important musicals (Merrily We Roll Along, Legs Diamond, Carrie) were so roundly ripped apart by preview word-of-mouth that they were almost doomed to failure. Since the appearance of internet chat rooms, it is possible for New York's theatre buffs to share intimate details of every preview. After critics dismissed Jekyll and Hyde, fans of the show quickly organized via the web, helping to keep the show alive. When Bernadette Peters missed several previews of Gypsy (2003), disgruntled fans had the word out on the web long before newspapers picked up the story.

Some shows have tried to extend previews endlessly and avoid the critics. Beatlemania (1977) postponed its opening for several months, playing to packed houses. Thanks to strong word of mouth, it then survived bad reviews and ran for several years. Others that tried to avoid the critics were not nearly as lucky. Sarava (1979) cancelled its opening three times, but even an amazingly aggressive ad campaign could not keep it open for more than 149 performances. Merlin (1983) tried the same tactics, folded after 199 performances, and lost millions.

New shows usually undergo revision during previews. Songs, scenes and bits of business that seemed fabulous during rehearsals are often scrapped. Now and then, a performer is replaced or a role is cut. When a show is in serious trouble, new songs and scenes may be added, but this is an expensive proposition. When Legs Diamond added a new opening number part way through previews, the orchestrations and extra rehearsal time cost tens of thousands of dollars. Although the number ("When I Get My Name in Lights") was a success, it was not enough to save an otherwise ill-conceived show.

Previews are also the time when all kinds of technical problems must be resolved. The massive turntable that kept Les Miserables flowing froze during previews, and the musical version of Shogun had critics in the audience when a runaway set knocked the lead actor out cold. The performance had to be stopped, and the critics returned a few weeks later. Their reviews were so scathing that it hardly seemed worth the wait.

Eventually, a show reaches that culminating moment – the opening night. Not all openings are created equal.

Next: Opening & Running