  The factor estimation process is a really challenging task for non-linear
models. Even whether researchers manage to successfully estimate model factors,
they still must estimate their confidence intervals, which could require a high
computational cost to turn them into informative measures. Some methods in the
literature attempt to estimate regions within the estimation search space where
factors may jointly exist and fit the real data (confidence contours), however,
its estimation process raises several issues as the number of factors
increases. Hence, in this paper, we focus on the estimation of a subregion
within the confidence contour that we called as Confidence Subcontour Box
(CSB). We proposed two main algorithms for CSB estimation, as well as its
interpretation and validation. Given the way we estimated CSB, we expected and
validated some useful properties of this new kind of confidence interval: a
user-defined uncertainty level, asymmetrical intervals, sensitivity assessment
related to the interval length for each factor, and the identification of
true-influential factors.
