Research minded practice in social work

Let's assume it would be reasonable to expect that social workers, involved in the lives of other people, should know what they are doing. That seems self-evident. We expect our doctors to know what they are doing when we go to see them. Why would it be different? But what does it mean to say we expect social workers to know what they are doing. Just what is it we expect them to know, and how would we know if they knew it? Not so easy. We might feel reassured if we checked up on their qualifications. At least we'd know they had some relevant education and training. Or, from word of mouth, we might hear they were good at their job. That helps. But, who is to say the education and training is adequate, or the grapevine is working properly? Why should I trust those social workers to have anything to do with my life?