def mcfadden_r2(ll_est, ll_null):
    """
    McFadden's Pseudo R-squared when the saturated model is not available.

    Parameters
    ----------
    ll_est : numpy array
        Estimated Log likelihood.
    ll_null : numpy array
        Null-model log-likelihood.

    Returns
    -------
    m_r2 : float
        McFadden Pseudo R-squared.

    """
    m_r2 = 1 - (ll_est/ll_null)
    return m_r2