  Two phenomenological models which give opposite predictions for the
$s$-${\bar s}$ asymmetry in the nucleon sea are re-analyzed carefully. It is
pointed out that although the quantitative results in both models depend
dramatically on the parameters, the predictions for the shape of $s(x)-{\bar
s}(x)$ in the two models are parameter independent and opposite. Thereby the
coming experiments are likely to be able to distinguish the two models. We find
that the reason for the two models giving opposite predictions is that the
fluctuation functions and parametrizations for the strange (anti-strange) quark
distribution in the baryon (meson) in the two models are quite different. To
further investigate these models, we use the same parametrizations for the
strange (anti-strange) distributions of the baryon (meson) in the two models.
We find that one of the models depends strongly on the parameter which controls
the behavior of the meson-baryon fluctuation function. Also the two models
agree on the shape and size of $s$-${\bar s}$ for some values of the model
parameters, but can disagree strongly for others.
