MADISON, Ill. – Somewhere in this world lies a notebook. Inside the notebook is a page that many around the IndyCar world would love to sneak a peek at.

The page contains a list. Four lists actually. On one side: the pros and cons of staying with Honda. On the other: the pros and cons of switching to Chevrolet.

The notebook — and its intriguing contents — belongs to Andretti Autosport Chief Operating Officer Rob Edwards.

“It sounds old-school,” Edwards says with a chuckle, “but we really weigh the pluses and minuses on each side and decide how it stands up. It’s really been a steady, considered process.”

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Edwards said Andretti has been has no plans to share the contents of his notebook with IndyStar or anyone else — not today at least. But someday soon, likely very soon, hints Edwards, the world will know which side won out.

“We’ve agonized over (this decision),” Edwards told IndyStar after practice for the Bommarito Automotive Group 500. “I think we’re getting, well, we have to, by definition, be getting to the end of the decision-making process because manufacture testing is going to happen at the end of the season and we’ll be left behind unless we’re in one camp or another.”

But even the end of the season is not soon enough for Edwards, who says Andretti will begin to fall behind in preparations for next year if a decision is not made soon.

“Certainly with my operations hat on and engineering hat on, I want the decision made as soon as possible," Edwards said. “Because it’s holding things up right now.”

Honda, Edwards explained, is not anxious to share much new information with the team right now. Chevrolet understandably feels the same way.

That is likely why when the second phase, the manufacturer phase, of testing for the new 2018 aero kits begins, an Andretti car will not be apart of it. While Schmidt Peterson Racing and Team Penske were Honda and Chevrolet's cars for the first phase of testing, IndyStar has learned that Chip Ganassi Racing and Ed Carpenter Racing will supply the cars for the second phase.

“Neither knows where we’re going to live,” Edwards said. “So it’s really to no one’s benefit to prolong it any longer than it needs to be. … We’re getting to that point of the year where it’s starting to be an issue. A month ago, three weeks ago, it wasn’t. But it’s getting to that point. From an operations standpoint, we need to get on with it.”

While Edwards was hesitant to reveal too much about the factors that are playing into the team’s decision, he did speak to the benefits of continuity and his happiness with the progress Andretti has made this season.

Winners of the past two Indianapolis 500s, the Andretti-Honda partnership has enjoyed fantastic and historic success in May, but Andretti had struggled on some street circuits over the past couple of years. This season though, Edwards said, has been a major step in the right direction at those places.

“We’ve made big gains this year,” Edwards said. "I think clearly there were some street circuits the last couple years where we were out to lunch. It was like, ‘Did those guys show up this weekend?’ I think we’ve shown up everywhere this year to greater or lesser extent. It’s frustrating we haven't won more races than we’ve won. But we’ve been competitive pretty much every weekend. We’ve seen definite gains in the right direction.”

Edwards was quick to point out their success this year wouldn’t preclude them from switching manufacturers, but he did say that he doesn’t believe the media and public have given enough weight to success when it comes to Andretti’s decision.

“It’s interesting, right,” Edwards said. “Everyone focuses on commercial aspects: ‘Andretti is going to Chevy because Chevy is offering more money. Or they are not going because they won’t pay more money.’ The reality is that so much more that goes into it. It can be purely just a commercial decision. If you’re not competitive on the race track, none of it matters, because you’ll lose the brand.”

Follow IndyStar Motor Sports Insider Jim Ayello on Twitter and Instagram: @jimayello.