From Longman Dictionary of Contemporary Englishhave a hand in somethinghave a hand in somethingTAKE PART/BE INVOLVEDto influence or be involved in something He had a hand in both goals. → hand
Examples from the Corpus
have a hand in something• Thorpe has had a hand in restoring the 21 houses.• They also agreed that the participants themselves should have a hand in deciding what they would discuss.