This is the validation I was using:
#Define validation validates :order_id, :user_id, :acknowledged, :completed, :presence => true
After another Google search I came across this post which shows how to validate a boolean value.
When implemented within my app, the new validation looks like this:
#Define validation
validates :order_id, :user_id, :presence => true
validates :acknowledged, :completed, :inclusion => {:in => [true, false]}
Hopefully that’ll be able to help a few of you out as well.