Island planning officials and the Martha’s Vineyard Commission have been taking advantage of a biennial opportunity to improve their relationship, which often swings between gratitude and irritation.

A six-member subcommittee of the commission has met several times with Island planning board members since September to pick apart the commission’s criteria for what it considers developments of regional impact (DRIs), which are by law subject to MVC review.

It has been widely acknowledged that the regional commission, with its unique powers, has helped save the Vineyard from the overdevelopment that has taken a toll on natural resources and rural landscapes across the state. At the same time, towns and developers on the Island have sought greater clarity in the DRI process.

The DRI checklist review is required every two years by law, but the commission has the final say in how to amend it, or whether to amend it at all. Under the guidance of new commission executive director Adam Turner, the checklist review subcommittee has actively solicited comment and critique. Town planning board members were explicitly invited to the table this time around, and some have attended nearly every meeting.

The committee is now in hiatus as commission staff members work to sift through the material collected so far and develop a report. Eventually the committee will regroup and discuss possible amendments and make a recommendation to the full commission.

“We are really only at the beginning of this process,” committee chairman Linda Sibley said. She expected deliberations to continue into the new year, especially in light of the volume of comment collected so far.

Most of the concerns have focused on the review process itself, the specific thresholds that trigger referrals, and the clarity of language in the checklist. In many cases, towns have sought more control over local permitting, and less ambiguity in terms of what qualifies as a DRI.

“We have seen several exceptions over the last few years of projects that should have been, in our opinion, a part of the DRI process and were not, and other projects that were possibly DRIs that we felt didn’t need to be,” Oak Bluffs planning board member Ewell Hopkins said. “The inconsistency . . . caused us extreme concern.”

Aquinnah planning board chairman Peter Temple, who has attended most of the meetings, advocated for streamlining what is called the concurrence process — where projects are referred but may not necessarily go on to review. And he hoped that towns would be able to opt out in cases where adequate rules were already in place.

“Determining concurrence is itself a very time consuming, multiple-week process,” Mr. Temple said. “My recommendation is that they find some way to simplify that.”

Edgartown planning board chairman Michael McCourt said he believes the commission plays an important role on the Island, but he also took issue with the DRI checklist. As one example, he pointed to a recent proposal for a subdivision on Mullen Way, which he said fell short of a 10-lot threshold for referral. During the town permitting process, the developer had redrawn the plans to include nine, rather than 10 lots.

“We try to handle everything that we can right at the town level, and we don’t think it’s necessary to have the commission involved in something that may be borderline,” Mr. McCourt said. But he added: “I’ve always had the opinion that if we get into a head-scratcher, we should refer.”

Mr. Turner agreed that changes are in order. “I would say that there needs to be more communication between the commission and the towns, both in how we receive these things, how we review these things, and what happens after we make a decision,” he said. “It’s clear that we need to coordinate everything better.”

Among other things, the committee plans to measure the frequency of each DRI trigger over time and propose ways to simplify the checklist. But how to involve the six towns is still unclear.

Another area of concern is commercial developments, which have made up the bulk of DRI reviews in recent years (a departure from the 1980s and 1990s when residential development occurred at a brisk rate on the Island).

Mr. Temple has pressed for an exemption for archaeological review in Aquinnah, where he said bylaws already protect those resources. Aquinnah is the only town on the Island that is entirely designated as a district of critical planning concern, a process done via the MVC enabling legislation.

Mrs. Sibley welcomed efforts by towns to develop more stringent regulations. “We’d be happy to turn more stuff back to the towns, provided that the town can make the kinds of decisions that are envisioned in our legislation,” she said.

Mr. Hopkins said town bylaws and MVC guidelines should inform each other. The commission has already begun sifting through the town bylaws. “That’s a monumental task,” he said. “I don’t have any expectation that it will be complete in this round.”

Towns have participated in a variety of ways. Mr. Turner recently attended a meeting of the Edgartown planning board and stayed on for a public hearing on a proposed expansion on Upper Main street. Planning board members bristled at the required DRI referral for additions of 1,000 square feet or more that result in a total of 2,000 square feet or more — and they made it clear.

“It was a good way to bring up the point,” Mr. McCourt said. But he also appreciated Mr. Turner’s willingness to hear the board’s concerns. “He gets it that there is an issue,” he said. “And I think the issue is resolvable.”