How do I make sure quiet workers get credit instead of the loudest?

You can see it happening on your team: recognition flows to whoever promotes themselves most loudly, while the steady people who do the real work go unseen. You have let visibility stand in for value, and the quiet contributors are quietly learning that doing good work without fanfare does not pay. That is a costly lesson to let them learn. As the one who hands out recognition, you have more power here than the loudest voices do. They can only speak up. You decide what actually gets rewarded. When you let volume win, you are not just being unfair to the quiet ones; you are training your whole team to perform instead of contribute, and slowly losing the very people who hold the work together. Start by looking past the noise on purpose. Before you next give credit, ask who actually did the work, not who told you about it, and go find out if you are not sure. Then recognize one quiet contributor plainly and specifically, in front of others. Do that consistently and you change what your team believes is worth being. Reward the work, and the work will follow.