The automaker says that the new policy is due to a change in the way it records financials for vehicles. In the first part of this year, GM started assigning profit and loss to the country in which a vehicle is sold, rather than to the facility at which it was manufactured. This, says GM, makes the production numbers less critical to keep track of.
Concerns about the change in reporting are multitudinous. Many automotive suppliers use production forecasts that are based on real production data to plan their own manufacturing schedules for coming months. What's more, Automotive News tells us that the GM numbers have been used in many other standard indicators of economic health in the US, including those published by the Federal Reserve. While models exist for estimating the production data, nobody is exactly sure how accurate they'll be, or what the longer term fallout in the industry will look like.