Scientific activity in the Humanities and Social Sciences (HSS) presents special characteristics that require the use of various sources and methodologies to adequately assess its impact and influence on both academic and non-academic audiences. This study aims to explore the validity of traditional and alternative information sources for the analysis of the characteristics of HSS research and its academic impact and influence (considering social, media, informative and political influence). It is also intended to highlight the differences between Humanities (H) and Social Sciences (SS) and analyse the variables that determine the different types of impact and influence of research in each of them. The following sources of information are used: Web of Science, conCIENCIA (institutional database), Google Scholar, Unpaywall, Altmetric.com and Overton, focused on the study of the Spanish National Research Council (CSIC). The results obtained show that institutional sources make local research visible, which has high percentages of open access. The usefulness of alternative sources to measure social, media, informative and political influence is verified, since HSS publications have an important number of mentions. Significant differences are observed between H and SS in terms of publication coverage (higher in H in the institutional database), language (more Spanish in H), open access (higher percentages in SS) and impact measured through conCIENCIA (the greatest number of documents with a high impact is found in H). In addition, the influence on non-academic audiences is increased by the international orientation of research, the greater academic impact, the participation of SS centres and the immediacy of publications. This study is a starting point for future research, as it explores several tools and data sources to analyse the influence of HSS research on different audiences. A comprehensive analysis will also facilitate the proposal of new metrics applied to the HSS assessment, highlighting its importance for society as a whole.