Preheat oven to 350º Fahrenheit. Line a baking sheet with parchment paper and set aside.
In a large mixing bowl, cream together the two sugars and the shortening until light and fluffy. Add in the eggs and vanilla and mix until well combined.
In a separate bowl, whisk together the baking soda, baking powder, salt, and flour. Slowly stir in the dry ingredients into the wet ingredients.
Next, mix in the oats on a low setting until evenly distributed. Turn the mixer off and gently fold in the raisins by hand.
Using a 1.5 tablespoon scoop, drop cookies onto the prepared baking sheet. Space them out evenly. You should be able to get 12 cookies on one sheet (three rows of four cookies).
Bake the cookies for 13 to 15 minutes. The cookies will still be soft and might look like they aren't done. If the center looks set, they are done. Remove and allow to cool for a few minutes before transferring to a cooling rack. Allow to fully cool before storing in an airtight container.