def measure_diff(fakes, preds):
    """Measures difference between ground truth and prediction

    fakes (float array): generated "true" global scores
    preds (list list): list of [video_id: int, criteria_name: str,
                                    score: float, uncertainty: float]
                            in same order

    Returns:
        (float): 100 times mean squared distance
                    between ground truth and predicted score
    """
    diff = 0
    for fake, pred in zip(fakes, preds):
        f, p = round(fake, 2), pred[2]
        diff += 100 * abs(f - p) ** 2
    return diff / len(preds)