Page 240 - Becoming Metric Wise

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Indicators

Table 7.10 An illustration of the calculation of the fourth (citation-chronological,
publication cumulated) and fifth (cumulative, citation-chronological, publication
cumulated) time series (case M 5 5, N 5 4)

Publication YY+1 Y+2 Y+3 Publication Y Y+1 Y+2 Y+3
year (row) year (row)
Citation year Citation year
(column) (column)
Y Y
Y+1 Y+1
Y+2 Y+2
Y+3 Y+3
Y+4 Y+4
YY+1 Y+2 Y+3 Y Y+1 Y+2 Y+3
Y Y
Y+1 Y+1
Y+2 Y+2
Y+3 Y+3
Y+4 Y+4
YY+1 Y+2 Y+3 Y Y+1 Y+2 Y+3
Y Y
Y+1 Y+1
Y+2 Y+2
Y+3 Y+3
Y+4 Y+4
YY+1 Y+2 Y+3 Y Y+1 Y+2 Y+3
Y Y
Y+1 Y+1
Y+2 Y+2
Y+3 Y+3
Y+4 Y+4
YY+1 Y+2 Y+3 Y Y+1 Y+2 Y+3
Y Y
Y+1 Y+1
Y+2 Y+2
Y+3 Y+3
Y+4 Y+4

the citation window has a length of 2, 3 or more years. The term publi-
cation age refers to the fact that citations are collected for documents
with increasing age. These sixth type time series are isochronous indica-
tors as used, e.g., in Liang’s theory on rhythm indicators (Liang, 2005;
Egghe et al., 2008). The seventh type is then a cumulating publication
age, chronological time series (Table 7.11).