Fractal analysis is now common in many disciplines, but its actual app
lication is often affected by methodological errors which can bias the
results, These problems are commonly associated with the evaluation o
f the fractal dimension D and the range of scale invariance R. We show
that by applying the most common algorithms for fractal analysis (Wal
ker's Ruler and box counting), it is always possible to obtain a fract
al dimension, but this value might be physically meaningless. The chie
f problem is the number of data points, which is bound to be insuffici
ent when the algorithms are implemented by hand. Further, erroneous ap
plication of regression analysis can also lead to incorrect results. T
o remedy the former point, we have implemented a convenient numerical
program for box counting. After discussing the rationale of linear reg
ression and its application to fractal analysis, we present a methodol
ogy that can be followed to obtain meaningful results.