Rates of pharmacokinetic literature obsolescence

Abstract

Obsolescence may be defined as the decline over time in validity or utility of information. To investigate pharmacokinetic literature obscolescence, two discrete methodologies were utilized. In the first type, the age distribution of 12,836 periodical references from 766 pharmacokinetic papers published in 16 journals and bearing a 1982 publication date was analyzed (synchronous study). The median reference citation age was 4.52 years, and 54.4% of all citations were to articles published in the prior 5 years. Using non-linear regression analysis, two groups or types of literature were tentatively identified. The first or ‘ephemeral’ type comprised about 98.5% of the sample and obsolesced with a 2.94 year half-life. The second or 'classic' type comprised about 1.5% of the literature and obsolesced with a 21.6 year half-life (there was, however, considerable imprecision in this latter parameter estimate). A historical or diachronous study followed quantitative citation patterns to 6 classic pharmacokinetic articles published in the 1960s. Citation counts were normalized to eliminate the influence of pharmacokinetic literature growth. The harmonic mean obsolescence half-life was 2.24 years. The results of both the synchronous and diachronous studies strongly suggest pharmacokinetics is characterized by an unusually high degree of rigor in methodology and data analysis, i.e. pharmacokinetics is a relatively ‘hard’ discipline.