For GetBidderList, you can reduce the ItemType fields and other fields returned by specifying one of two values in the GranularityLevel field, Coarse or Medium. If you specify Coarse, the primary fields returned are the following: Item.ItemID and Item.ListingDetails.EndTime. If you specify Medium, an abbreviated result set is returned that includes many more fields than in the case of Coarse, including the following: Item.BuyItNowPrice, Item.Currency, Item.Site, and Item.Title.
See the
Field Index to learn which calls use GranularityLevel.