Evolutionary Biological Data Science Laboratory

characteristic time scale of scientific activity

The characteristic time scale of scientific activity of a researcher (t_h index) (Popov 2005) is the amount of time from the present to the past accounting for publications to which the researcher receives half of their citations. Put another way, if one sums a researcher's citations in reverse chronological order by publication, it is the number of years necessary to reach half of their total citations.

Example

Publications are ordered by year of publication, from most recent to oldest.

Year (Yi)	2001	2001	2001	2001	2000	2000	2000	2000	2000	1999	1998	1998	1997	1997	1997	1997	1997	1997
Citations (Ci)	1	1	0	0	12	2	1	1	0	4	16	0	57	26	11	10	3	0
Cumulative Citations (ΣCi)	1	2	2	2	14	16	17	18	18	22	38	38	95	121	132	142	145	145
													½CP = 72.5

The first year where ΣC_i ≥ ½C^P is 1997, thus the characteristic time scale of scientific activity is 2001 − 1997 + 1 = 5

History