# Michael S. Rosenberg’s Laboratory

Computational Evolutionary Biology & Bioinformatics

E-mail: msr@asu.edu
← Back to introduction

## dynamic h-type-index

The dynamic h-type index (Rousseau and Ye 2008) is a measure of both the size of the core as well as how the core is changing through time. The basic index is

$$h_{dyn}=R\times v_h,$$where R is the R-index and vh is a measure of the rate of change of h through time. Rousseau and Ye (2008) suggest a number of ways to estimate vh, including that it be determined over a fixed time interval (e.g., 5 or 10 years) to make it more contemporary. They also suggest one use the rational h rather than h because its finer grained resolution will allow for better estimates of the rate of change of h.

Here vh for a given year is estimated as the slope of the regression of the rational h-index against year for all data points up through that year.

Yearhdyn
1997n/a
19984.4000
19996.6283
200010.9350
200115.0981
200219.0343
200324.4989
200432.9927
200541.9522
200651.6689
200760.7735
200870.3918
200983.8064
201093.6022
2011102.1754
2012108.1961
2013115.4276
2014124.2882
2015131.6627
2016137.4018
2017139.2489

## References

• Rousseau, R., and F.Y. Ye (2008) A proposal for a dynamic h-type index. Journal of the American Society for Information Science and Technology 59(11):1853–1855.