"I feel like there's more urgency," Chang said in an interview, adding: "You feel like you're part of this global community."
It's not what he expected. Not while working as a reporter for Fujian Television in China, nor while studying mass communication as a doctoral student at Purdue University.
Chang may be the most famous professor that people have never heard of - producer, researcher, writer, and director of groundbreaking movies that have been screened across the United States and in countries from Canada to China.
On Nov. 20, he will speak at a screening of Long Wait for Home and Daughters' Return at the Lawrenceville Library in Lawrenceville, N.J. All 35 seats have been claimed.
His films revolve around the repercussions of China's one-child policy, which has resulted in the wide abandonment of baby girls - and transformed the way many Americans build their families.
The Chinese government has made it illegal to have "extra" children, but also to place children for adoption. Because sons are prized culturally, newborn girls are often secretly left on street corners and in bus stations, then swept into orphanages.
Chang has not only found people who were deemed unfindable - including birth parents, who could face prosecution - but persuaded them to talk on camera.
"Amazing stories. We learn a lot from them," said Kay Ann Johnson, a scholar at Hampshire College and perhaps the nation's foremost authority on China's orphanages and birth policies. "He does a good job of unpeeling the onion, and doing it responsibly, and leaving lots of questions open."
Last month, Millersville screened Chang's latest film, Sofia's Journey, as part of a discussion of ethnicity during the One Campus, One Book program.
Millersville is an 8,700-student state school amid green, rolling hills about 75 miles west of Philadelphia. Chang landed there for a simple reason: He needed a job. As he finished his doctorate, he sent out applications, and Millersville replied not just with interest but with an offer.
He teaches communications, television, and speech, and he travels to China each summer to film - taking students with him, so they can gain hands-on experience in handling sound and cameras on what are often emotional interviews.
"There are things about his movies that give us a jolt, that even make us a little uncomfortable. I think that's very valuable," said Peggy Scott, a past president of the Northern California chapter of Families with Children from China, who grew up in Jenkintown. Her daughter, Abigail, is a college freshman.
Chang came to the United States in 1995, his view on overseas adoption one that many continue to hold: Good for kids who need parents and parents who want kids. But as he worked on his first films, he saw cutting issues of race and identity. And he saw that, having grown up in Jiangsu province and settled in Lancaster County, he held a unique position between the cultures.
For instance, he said, in the West, a blood tie is not so important and adopted daughters are treasured. In the East, the bloodline is everything, so sons are paramount. In the West, the question of "who am I?" is crucial, pushing many adoptees to search for birth parents. In the East, that question is secondary at best.
Ask Chang his age and he has to think, his precise birthday not so significant. (He turns 48 this month.)
"As our children are getting older, they have questions that are not answered, and that we as parents can't answer," said Sarah Davies, president of FCC-Delaware Valley and mother to 6-year-old Kate. "The kind of work he's done is really important."
Sofia Robinson is a teenage artist, singer, and dancer who was adopted in 1995. For as long as she can remember, she says in Sofia's Journey, she has wanted to find her birth parents.
The film follows the Robinson family as they travel from Colorado to China to search - and discover something more complicated than they could have imagined: A Chinese family who had informally adopted Sofia at birth, and who fully intended to keep and raise her.
To them she was not Sofia but Jing Jing, the perfect complement to their son.
The father, Ouyang Bo, says on camera that intense outside pressure - which he won't specify, but doubtless came from birth-planning officials - forced the couple to give their daughter to an orphanage when she was 7 or 8 months old.
"I'm sorry, I'm sorry," the mother, Chen Nibi, says to Sofia. "We think about you all the time."
They show Sofia photos of herself as a baby, take her to where they strolled as a family, tell her she's the double of her biological mother, who lived with them for a time.
Sofia is thrilled and wants to know more about her birth parents: Did they love to sing and dance like she does? Why, she asks haltingly, didn't they keep her?
But when pressed, the Ouyangs offer different accounts of how Sofia came to them. They say they can't remember the name of her birth mother. In the film, it's plain that the Chinese family loves Sofia and mourns losing her - and that they're not telling her the whole story.
At a banquet, the Ouyangs serenade Sofia, common at Chinese celebrations. She responds with a song from Disney's Mulan, about a Chinese girl forced to pretend she is someone else.
For more than a decade, prospective parents flocked to the world's most efficient adoption program, attracted by its clear, uniform rules and liberal attitudes. Most of all, people were drawn to China because the one-child policy explained why children were available.
But international adoption has changed dramatically in China and elsewhere, as countries have limited the pool of applicants, reduced the number of available children, or closed their programs. Foreign adoptions fell from 22,991 in 2004 to 11,058 in 2010. Last year, China adoptions numbered 3,401, half the 2005 peak.
More recently the narrative around the one-child policy has been upset by news that officials in Hunan seized babies and sold them into a lucrative black market. In August, the New York Times reported that at least 16 children were taken between 1999 and 2006. Officials threatened big fines against couples who had "illegal" births, then took children when parents could not pay.
Chang said he believed China's system was basically clean. At the same time, his films show that girls enter orphanages in many different ways, with complicated backstories, and that official accounts may not bear scrutiny.
"I have to give him a lot of respect for forging that area of 'Let's really find out,' " said Deborah Johnson, a Korean adoptee who heads Kindred Journeys International, a heritage travel firm in Minneapolis. "It's not just this blanket one-child policy. It's much more complex."
Last summer, before Susan Morgan traveled from Ambler to Jiangxi province with her eldest daughter, she made sure that Anna, 14, and her sister, Mary Ruth, 13, saw Chang's latest films, Sofia's Journey and Daughters' Return.
Both girls want answers about their Chinese parents, Morgan said. The films "helped educate us about some of the emotional hurdles" of searching and "helped me realize how elusive the truth can be."
Chang's next movie will tell the story of an adopted girl who at 18 goes to live with her birth family in China, confronting new relationships with kin who are essentially strangers. He expects Ricki's Promise to debut next fall. He's not sure what might follow, but knows there is another film ahead.
"Some people might say the Chinese adoption program is dying out," Chang said. "That doesn't mean the needs aren't there."
Contact staff writer Jeff Gammage at 215-854-2415, email@example.com.