  The phase structure of SUSY gauge theories can be very different from their
nonsupersymmetric counterparts. Nonetheless, there is interesting information
which might be gleaned from detailed investigation of these theories. In
particular, we study the precise meaning of the strong interaction scale
$\Lambda$. We ask whether one can meaningfully apply naive dimensional analysis
and also ask whether the study of supersymmetric theories can shed light on the
apparent discrepancy between the perturbative scale $\Lambda_{QCD}$ and the
``chiral lagrangian'' scale $\Lambda_\chi$. We show that in N=1 supersymmetric
Yang Mills theory, ``naive dimensional analysis'' seems to work well, with
$\Lambda_\chi$ consistently equal to the scale at which the perturbatively
evolved physical coupling becomes of order $4 \pi$. We turn to N=2 theories to
understand better the effect of instantons in accounting for the QCD
discrepancy between scales. In N=2 supersymmetric SU(2) the instanton
corrections are known to all orders from the Seiberg-Witten solution and give
rise to a finite scale ratio between the scale at which the perturbatively
evolved and ``nonperturbatively evolved'' couplings blow up. Correspondingly,
instanton effects are important even when the associated perturbatively evolved
gauge coupling only gives $\alpha$ of order 1 (rather than $4 \pi$). We compare
the N=2 result to instanton-induced corrections in QCD, evaluated using lattice
data and the instanton liquid model, and find a remarkably similar behavior.
