Michael Keaton, Liev Schreiber, Mark Ruffalo, Rachel McAdams, Brian d'Arcy James, John Slattery and Mark Ruffalo in "Spotlight"

When Tom McArdle first met Tom McCarthy in 2002 for the actor-turned-director’s first film, the delicate grief-riddled drama “The Station Agent,” the two bonded quickly over their shared passion for “Local Hero,” Bill Forsyth’s gentle 1983 comedy about an oil company employee (Peter Riegert) charged by his boss (Burt Lancaster) to establish a refinery in a small fishing village in Scotland who suffers a crisis of conscience once he actually sees the village for himself. Although the film was a reference to the tone McCarthy wanted for his debut, it was an ideal introduction to the four others that followed as well, all revolving around those who summon an inner strength they might not have been aware they had to do what they believe is right in ways that don’t call attention to themselves.

Tom McArdleAs an editor, McArdle has been similarly modest in his collaborations with McCarthy,‎ crafting quiet but powerful character studies such as “The Visitor” and “Win Win” where the accumulation of small details often amount to big emotional moments. There is no shortage of those in the pair’s latest film “Spotlight,” but there was a greater challenge at hand in dramatizing the Boston Globe’s investigation of Roman Catholic priests hidden by the Church for their egregious sexual misconduct involving the youngest members of their clergy. A story that had been exhaustively reported and easily could be sensationalized, the filmmakers had the daunting task of ‎creating a compelling narrative while sticking to the facts of the grueling process for the four reporters – Walter “Robby” Robinson (Michael Keaton), Sacha Pfeiffer (Rachel McAdams), Mike Rezendes (Mark Ruffalo), Matt Carroll (Brian d’Arcy James)- and their editors Ben Bradlee Jr. (John Slattery) and Marty Baron (Liev Schreiber)‎ who went up against one of their city’s most powerful institutions to report something few in the community were willing to speak about.

Surely much of the film’s elegance comes from the meticulous script penned by McCarthy and Josh Singer, but McArdle’s craftsmanship in the edit plays an equal role in parsing out just enough details to simultaneously inform and intrigue at any specific moment and gives each member of the fine and varied ensemble their due. It turns out that not unlike the Spotlight team that honed their reporting over time, McArdle and McCarthy have been able to do the same with their process of working together over the course of nearly a decade-and-a-half. Recently, McArdle, who has done similarly superlative work in recent years with Lake Bell (“In a World”) and Todd Louiso (“Hello I Must Be Going”) shed light on how that process has been refined over the years, creating the momentum of the reporters’ chase for the truth, and why he’s fond of working with directors who come from an acting background.

Rachel McAdams, Mark Ruffalo, Brian d'Arcy James, Michael Keaton and John Slattery in "Spotlight"Since you’ve worked with Tom McCarthy from the start of his directing career, has your collaborative process evolved?

“Spotlight” is our fifth film together and we have gained a lot of experience through the years. We trust each other and have a pretty comfortable collaboration. Our budgets have gone up, which is nice since it lets us have more time in the edit. Also we have developed a working process that we like. One thing that we always do is a two-day pickup shoot in the middle of the edit where we get inserts and transition shots and new pieces for montages and little scenes to fill a hole or add information.

We also like to screen the film every three weeks for a small group in the edit room. We’ll sit behind people and get a feel for their reactions and where the film is playing well or isn’t.  Then we’ll talk to them afterwards and get their feedback about what information they’re tracking and what they’re not following. The next day, we will make adjustments based on both the feedback and our gut reactions to the cut.

What were the challenges for “Spotlight”?

Mainly, it was making sure that people were following all the information, and keeping the story moving. There were also some big montages to cut, that had a lot of footage—a lot of shots of church directories, computer screens, people knocking on doors and so forth. There were some big scenes like the one in Marty’s office towards the end that had most of the cast in one room and a lot of coverage shot from both sides of the actors that took a while to piece together.

Then there were more specific issues. At one point, people were feeling like the 9/11 sequence wasn’t working, so we dropped a scene out of it to keep it moving. People just didn’t want to be away from the investigation for too long. At another point, people were not understanding what was happening with the documents, so we had Mark Ruffalo come in and re-record some off-camera phone dialogue with Robby so people could understand why those particular documents were so important. Later on, people had some questions about Ben, so we added a scene between Ben and Mike in the vestibule of Mike’s building to give a little more insight about Ben. We also kept cutting back on scenes about the reporters’ personal lives. It always seemed like we just wanted to focus on the investigation. There were a lot of challenges over eight months [of editing].

Rachel McAdams, Michael Keaton and Mark Ruffalo in "Spotlight"What was it like working with an ensemble like you have for “Spotlight”?

It was incredible to have so many talented actors in the cast.  It kept the energy up to keep shifting between the four main Spotlight team members from scene to scene. In addition to the Spotlight team, who are all top-notch, every day during the shoot somebody great would show up. One day it’s Billy Crudup, and the next it’s Stanley Tucci, and the day after that it’s Paul Guilfoyle. And then, on the speakerphone, we have Richard Jenkins. Every day it was a nice surprise to see who was going to show up.

You’ve said before that you actually would give Liev Schrieber’s character Marty Baron a few extra beats in places. Was there actually much you could do with crafting the characters in that way?

In the early scenes with Marty Baron, since he is an outsider, I often gave him an extra beat before he spoke, to set him apart. Others might talk fast or overlap, but he does not.  So, even in his speaking rhythm, he is an outsider. With [Mark Ruffalo’s character] Mike Rezendes and his Spotlight team members, I would often cut their stuff tighter, and sometimes I would let them overlap, since they are comfortable with each other and Mike is very energetic.

I couldn’t help but notice that your last six films, including your last three collaborations with Tom, have been with actors-turned-directors. Is there something different about those collaborations?

Actors-turned-directors tend to care a lot about the performances in a film, and they seem to prefer films that are actor-driven. I think once I cut a few films like these that actors liked, I kept getting offered more of the same. Also, actors that become directors are generally pretty collaborative since they are used to working on-set with other actors and directors. They are all pretty energetic, too, since they all stay in shape for acting, which is helpful during the marathon job that is six to eight months of editing. They are all good to work with — Tom McCarthy, Lake Bell, Todd Louiso, and John Slattery — and I hope they all make more films.

“Spotlight” is currently in theaters.