  Dimensionality of parameters and variables is a fundamental issue in physics
but mostly ignored from a mathematical point of view. Diffculties arising from
dimensional inconsistence are overcome by scaling analysis and, often, both
concepts, dimensionality and scaling, are confused. In the particular case of
iterative methods for solving non-linear equations, dimensionality and scaling
affects their robutness: while some classical methods, such as Newton, are
adimensional and scale independent, some other iterations as Steffensen's are
not; their convergence depends on the scaling, and their evaluation needs a
dimensional congruence. In this paper we introduce the concept of adimensional
form of a function in order to study the behavior of iterative methods, thus
correcting, if possible, some pathological features. From this adimensional
form we will devise an adimensional and scale invariant method based on
Steffensen's which we will call ASIS method.
