Table 4 Indicators for scientific literatures and patent analysis
From: Assessment of technological level of stem cell research using principal component analysis
Indicators | Description | Calculation | |
|---|---|---|---|
Number of patents | Quantity of patents | The number of patents issued by the United States Patents and Trademark Office | |
Patent Impact Index | Quality of patents | \({\text{PII}}_{\text{a}} = \frac{{\frac{{{\text{C}}_{\text{a}} }}{{{\text{N}}_{\text{a}} }}}}{{\frac{{{\text{C}}_{\text{t}} }}{{{\text{N}}_{\text{t}} }}}}\) | Ca = the number of forward citations of patent in nation a Na = the number of patent in nation a Ct = the number of total forward citations of patents Nt = the number of total patents |
Number of papers | Quantity of scientific literatures | The number of scientific literatures published by the Scopus | |
Paper Impact Index | Quality of scientific literatures | \({\text{PII}}_{\text{a}} = \frac{{\frac{{{\text{C}}_{\text{a}} }}{{{\text{N}}_{\text{a}} }}}}{{\frac{{{\text{C}}_{\text{t}} }}{{{\text{N}}_{\text{t}} }}}}\) | Ca = the number of forward citations of scientific literature in nation a Na = the number of scientific literatures in nation a Ct = the number of total forward citations of scientific literatures Nt = the number of total scientific literatures |