In a medium bowl, stir together the oats, flour, baking soda and brown sugar. Cut in the shortening until the mixture resembles cornmeal. There should be no lumps of shortening left. Measure 1/2 cup of the mixture into re-sealable bags or containers for storage. Label and date each bag. This mix can be stored in a cool dry place for up to 12 weeks.
To make the cookies, empty one package of the mix into a bowl. Stir in 2 teaspoons of water, 1 tablespoon of raisins and 1 tablespoon of mini semisweet chocolate chips. Mix well and shape teaspoonfuls of dough into small balls. Place balls on an ungreased cookie sheet and flatten with the buttered bottom of a glass dipped in sugar. Follow you oven's instructions for baking.