def computeDerivatives(oldEntry, newEntry):
    """
    Computes first-order derivatives between two corresponding sets of metrics

    :param oldEntry: Dictionary of metrics at time t - 1
    :param newEntry: Dictionary of metrics at time t
    :return: Dictionary of first-order derivatives
    """
    diff = {k: v - oldEntry[k] for k, v in newEntry.items()}
    return diff