Altmetrics is a quantitative measure of the quality and amount of attention that scientific work receives through social media, citations, and article downloads.
Altmetrics do not reflect the same concept of impact as citations. Also, altimetric counts do not always present better filtering of highly cited publications than journal citation scores. Altmetrics scores are able to identify highly cited publications with higher levels of precision than journal citation scores (JCS), but they have a lower level of recall.
Dear colleague Manal Hadi Kanaan , thank you for your reply. I understand that altmetrics scores do not have the same level of filtering as other bibliometric indicators. Unless I'm mistaken, I think the difference lies in the main objectives of each of these indicators. Journal citation scores (JCS), impact factors, index H are registered only in the interactions between the community of researchers and that of publishers. On the other hand, the altmetrics score takes into account the interactions between the general public, via social networks, and the research community. It gives another value to scientific research, it allows the research community to measure even with uncertainties the level of sociatal appreciation.