By Jordan Wright (Photo/Margot Schulman)

A good indicator that Arena Stage’s production of “Dear Evan Hansen” is a production in flux is the playbill’s last minute insert — a list of the 16 musical numbers in the show and the characters that sing them — decisions undoubtedly made after the printing.

But if you watched the much-beloved, now-cancelled “Smash,” you’d know that was a key aspect of the TV show’s storyline. Benj Pasek and Justin Paul are the show’s musical team and lyricists, both alumni of the romantic drama that focused on the angst of creating a hit Broadway show.

In this coming-of-age musical written by Steven Levenson and directed by Michael Greif, Evan Hansen (Ben Platt, best known as the male lead of the “Pitch Perfect” films) is an angst-ridden teen, raised by a single mother (Rachel Bay Jones) in the age of social media. An outcast at school, his psychologist prescribes anti-anxiety meds and the self-examining exercise of writing letters to himself.

But that alone won’t curb the bullying and cure his aimless life until the day Connor Murphy (Mike Faist), a fellow outcast, takes his own life and a series of seemingly unconnected events converge to give Evan a purpose and an imaginative explanation for his broken arm. “You play who you have to play,” one person tells Evan.

The show has all the elements necessary to captivate — an absorbing story, tremendous cast, catchy, emotionally affecting tunes (backed by a 16-member choir), the brilliant music director Ben Cohn with orchestrations by Alex Lacamoire, and a hot topic. The problem is it’s overly long, causing it to drift into a number of obfuscating side stories.

Jennifer Laura Thompson and Michael Park are terrific as Connor’s bereaved parents and Laura Dreyfuss is engaging as Zoe Murphy, Evan’s love interest, and Will Roland and Alexis Molnar hit all the right emotional and comedic notes as Evan’s pals. But the show loses momentum as the characters’ roles are overly fleshed out and subplots stretch into distractions. Another issue is the annoying repetition of lyrics and all too frequent use of falsetto in the songs.

And although an intriguing device, Connor’s ghost, who haunts Evan and becomes his raison d’être, is more reminiscent of Ebenezer Scrooge than a reality check for Evan, as it eats up a great deal of the plot.

Instead, enjoy set designer David Korins’ furnishings drifting onstage via half-moon tracks and projection designer Peter Nigrini’s fantastic backdrop of text messages and emails projected onto a series of two-story sliding scrims and spilling out onto the stage floor. The messages serve to remind us of the influence of Facebook and Twitter on teens and the impact of online written word to enhance or endanger their lives with a single keystroke. The story has more sociological and psychological messages than Dr. Phil and “Days of Our Lives” combined.

Still, despite the thought of tweaks and cuts, you can rest assured its message will captivate Millennials raised in a world of student warehousing, cyber-bullying, secret email accounts and electronic devices. There is an important story to be told here. It just needs work.