Mix flour, brown sugar, and 1/4 granulated sugar in a mixing bowl. Cut in butter with a pastry blender until mixture is crumbly. Stir in oatmeal and pecans. Reserve 1 cup of the mixture and set aside. Press the remaining mixture into a 13x9 baking dish that has been lined with foil that has been greased. Preheat the oven to 350 degrees. Bake for 15 minutes.
Beat cream cheese, remaining granulated sugar, eggs, pumpkin, and pumpkin pie spice in a separate bowl on medium speed until well blended. Pour mixture over baked crust. Sprinkle with reserved crumb mixture.
Bake for 25 minutes. Let cool completely. Lift foil from dish and cut into 24 squares.