def confidence_score(reviews):
    if not reviews:
        return 0

    ratings = [r.get("rating") for r in reviews if isinstance(r.get("rating"), (int, float))]
    if not ratings:
        return 0

    avg = sum(ratings) / len(ratings)
    volume_factor = min(len(ratings) / 100, 1)

    return round(avg * volume_factor, 2)