Page 212 - Journal of Library Science in China, Vol.47, 2021

Ronda J. ZHANG & Fred Y. YE / Measuring knowledge hardness for quantifying backbone knowledge 211

W=W(P)=kP (2)
Thus, when the exact words are difficult to count, W in equation (1) can be directly replaced by
the page count P.
H= F+T (3)
P
This formula, when applied to calculate the volume of text in foreign or Chinese works,
might introduce certain systematic errors (for instance, varying word counts in different editions
of foreign publications or differing numbers of Chinese characters per page). However, it is
comparable within the same category. Both Formula (1) and Formula (3) can be multiplied by
100% to be transformed into percentage parameters.
Whether it’s Formula (1) or Formula (3), in practical application, they can only be used to
measure the knowledge hardness of a single piece of work or publication. In order to compare
across different disciplines, a simple and feasible assumption is: the knowledge hardness of a
standard textbook of a discipline represents the knowledge hardness of that discipline.

3 Applications

Based on the aforementioned formula for disciplinary knowledge hardness Formula (3), we
selected representative standard textbooks from both domestic and international sources for various
disciplines. We then conducted actual measurements of the knowledge hardness across these
disciplines and discussed their potential applications. The chosen disciplines and their standard
textbooks are:
(1) Physics: Feynman’s Lectures on Physics - Volume 2 (The Feynman Lectures on Physics,
2020 edition, Volume 2, in Chinese)
(2) Medicine: Goldman-Cecil Medicine (Goldman-Cecil Medicine, 25th edition, 2016, in
English)
(3) Economics: Samuelson’s Economics (Samuelson & Nordhaus. Economics, 19th edition, in
Chinese)
Measurement data is presented in Table 2.

Table 2. Knowledge hardness of selected standard textbooks in three disciplines
Parameter Feynman’s Lectures on Physics Goldman-Cecil Medicine Samuelson’s Economics

F 468 33 30
T 1, 249 2, 671 205
P 870 2, 556 756

H 1.97 1.32 0.25