Page 245 - Becoming Metric Wise

236 Becoming Metric-Wise

Table 7.14 Determination of an outgrow or CR index
Rank Article Received citations

1 R5 56
2 R4 23
3 R7 10
4 A 9
5 R2 8
6 R1 2
7 R8 1
8 R3 0
9 R6 0

where R(A) denotes the rank of A in this list. In case of ties we use an
average rank.
An example of the calculation of a CR-index. Table 7.14 presents
article A, its nine references (denoted as R followed by a number) and
received citations at a given moment of time.
4
For this table the outgrow index of article A is equal to 1 2 5 0:6.
10
If A had received one more citation it would have ended at a joint third
3:5
position and its outgrow index would have been 1 2 5 0:65. The
10
term “outgrow index” is used as it determines to which extent article
A has outgrown, in terms of citations, its own references. Hence, this
indicator is best seen in the context of a time series. Indeed, at the
moment of its publication article a has zero citations while all its refer-
ences have at least one. This means that at the moment of publication
CR(A) 5 0. The interesting question is then: will A rise in rank (will its
CR-index increase) and maybe reach the number one position. It should
be noted that when an article cites one or more ‘classics’ reaching the first
position is highly improbable.
CR(A) is always a number between zero (included) and one (not
1
included). When A is ranked first its CR(A)is equal to 1 2 .
TRef ðAÞ 1 1
This number is higher for long reference lists than for shorter ones. This
implies that being the first among 100 is considered “better” than being the
first among 10. Recall that articles that cite an article from A’s reference list
form the set of all articles which are bibliographically coupled with A.
Instead of considering the number of citations received by each element
in ER(A) we may also take the number of references in each of these