Time invested in researching and collecting documents is important in academic and industry world. Although non-linear methodologies are more accurate, it is known that very high computational support and longer study time are required. For this reason, in professional practice, more simplified methodologies are chosen, such as linear analyzes. However, there is a lack of specific information to determine in which cases the error that would be incurred by using a linear analysis is acceptable or significant. In the present investigation a series of cases are developed where the use of linear static analysis is acceptable, in contrast to scenarios where its use shows erroneous results. Simulations were performed in the commercial software ETABS to 12 structures using 3 analysis methods: linear static analysis, linear-spectral modal analysis and linear time-history analysis. The buildings, made of reinforced concrete, contain significant differences between them, both in height and in irregularity. The structural characteristics of all models comply with the requirements provided by the peruvian building regulations. The maximum mezzanine drift and basal shear were the parameters determined to make the comparisons. It is concluded that the static method is highly recommended for low-rise buildings, regardless of the irregularity of the building. However, for high-rise buildings, irregularity considerably influences the efficiency of the static method, this is reflected in the drift and shear results, whose values ​​obtained with respect to the modal method differ by up to 35%.