Knowing the scientific performance of a researcher, thematic, discipline, area of knowledge or country is an essential activity to subsidize and guide institutional or governmental scientific policies. Therefore, it is necessary to have consistent and reliable evaluation criteria for the performance of the evaluated and to consider qualitative and quantitative aspects in the analysis. Among the impact indicators present in the scientific literature, the h-index, proposed by Jorge Hisch in 2005, stands out as a robust evaluation parameter for simultaneously evaluating aspects related to productivity and to scientific impact of the evaluated researcher. Although h-index is a simple measure to obtain and its performance has been the most significant in the representation of the scientific performance of a researcher, several subsequent works pointed out their deficiencies and limitations and proposed variations in order to minimize or solve the problems. In this context, this Thesis aimed to analyze the h-index, its properties, variations and weights and propose two new complementary indicators to the h-index, called indexes dci and dco, dedicated to measure the dispersion of the h-index. It is hypothesized that these new indexes can contribute to evaluate the representativeness of the h-index as an indicator of the cumulative scientific impact of a researcher and to distinguish, more accurately, selective and productive researchers. In addition, it contributes to estimate the possibility of the evaluated author increasing his h-index by analyzing the dispersion of the number of citations contained in the h-core and also outside it. To verify the validity of the indicators as measures of dispersion, it was taken the group of 20 most productive authors of the Scientometrics journal, in the 35-year period (1980-2014), equivalent to the publication of at least 20 scientific articles. It was considered a second universe of analysis, in the Brazilian context, related to the 116 researchers with productivity scholarship in Qualis1 Research (PQ1) in Mathematics, and it were compared the h-index, some indicators of type h present in the literature and the indices dci and dco. For both universes, the total number of articles published, the number of citations per article and the year of publication were raised in the Scopus database for each researcher. From the data collected, the indices of each researcher were calculated. In conclusion, in both situations, the cientificometric indicators (h and h-type indices) complement and assist in the identification of authors with high productivity in a thematic. The dci and dco dispersion measures were able to reliably characterize the dispersion of the researcher's performance around his h-index and, consequently, the pertinence of the representativeness of this index as an indicator of the scientific performance of the evaluated researcher. These dispersion measures also allowed to distinguish in a more accurate way the performance of the researchers of the same scientific field.