Evolutionary Biological Data Science Laboratory

π-index

The π-index (Vinkler 2009) is similar to other measures of the quality of the h-index core, except that it uses its own unique definition of the core. For this index, the core publication set P_π is defined as the square-root of the total number of publications, truncated down to the nearest integer (e.g., for 80 publications, the square-root of 80 is 8.944, so P_π would equal 8):

$$P_\pi=\text{floor}\left({\sqrt{P}}\right).$$

The π-index is 1/100^th of the total citations within this core:

$$\pi=\frac{C^\pi}{100}=\frac{\sum\limits_{i=1}^{P_\pi}{C_i}}{100}.$$

Example

Publications are ordered by number of citations, from highest to lowest.

Citations (Ci)	57	26	16	12	11	10	4	3	2	1	1	1	1	0	0	0	0	0
Rank (i)	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
				Pπ = 4

The π-core is the floor of the square-root of the total number of publications, thus P_π = floor(√18) = floor(4.24) = 4. The π-index is 1/100^th of the sum of the citations within the π-core, thus π = 111/100 = 1.11.

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