Is it possible to compare researchers with different scientific interests?

The number h of papers with at least h citations has been proposed to evaluate individuals scientific research production. This index is robust in several ways but yet strongly dependent on the research field. We propose a complementary index h(t) =h(2)/N-a((T)), with N-a((T)) being the total number of authors in the considered h papers. A researcher with index h, has h, papers with at least ht citation if he/she had published alone. We have obtained the rank plots of h and ht for four Brazilian scientific communities. In contrast with the h-index, the ht index rank plots collapse into a single curve allowing comparison among different research areas.