**3.2. Relationship between feature values of patents and their patentability**

Although many "quality indicators" have been proposed, it might be questionable whether all of them exactly reflect patent quality. Since they each focused on different aspects of patents, they might represent different features of patents, not all of which represent "quality." To facilitate a precise understanding of the results of analysis of patent-paper citations from patents with high-"quality indicators" (hereafter they are called as "feature values" since they were not necessarily representative of quality), and the meaning of the new indicators proposed in Section 5, here I tried to show differences in meaning of the various major patent feature values.

In this subsection, I focused on the relationship between the three major feature values of patents: patent family size, forward citations (hereafter it is called as patent-patent forward


**Independent variable**

Other

ECB −0.806569

**(a) Cited/not (b) Large patent** 

University −0.281680 \*\*\* −0.42518 \*\*\* −0.35581 \*\*\*

AGS −0.268111 \*\*\* −0.39318 \* −0.91885 \*\*

CPS 0.296150 \*\*\* −2.09236 \*\*\* 0.80914 \*\*\*

**family (> = 15)**

**(c) High patent-patent forward citation (top** 

**(d) High patent generality index (> = 0.85)**

159

http://dx.doi.org/10.5772/intechopen.77130

**1%)**

Exploring Characteristics of Patent-Paper Citations and Development of New Indicators

**Coefficient Coefficient Coefficient Coefficient**

(Intercept) −2.504476 \*\*\* −4.30065 \*\*\* −4.91949 \*\*\* −5.27141 \*\*\* Review 0.125596 \* 0.29487 \* 0.30569 \* 0.20671 . Int Coauthored −0.09241 0.08866 . IF 0.269865 \*\*\* 0.15193 \*\*\* 0.14490 \*\*\* 0.13507 \*\*\* Top 10% 1.417856 \*\*\* 1.42854 \*\*\* 1.65927 \*\*\* 1.59834 \*\*\*

Publ Inst −0.038220 . −0.36932 \*\*\* −0.11208 . 0.17765 \*\*\* Corporation 0.837952 \*\*\* 0.83858 \*\*\* 0.81681 \*\*\* 0.62083 \*\*\*

BBI 0.895510 \*\*\* 0.33564 \*\*\* 0.57985 \*\*\* 0.85431 \*\*\* CHE 0.044250 . −0.35768 \*\*\* 0.13846 \* 0.76895 \*\*\*

ENE −1.403637 \*\*\* −2.40567 \*\*\* −1.92041 \*\* −1.21992 \* ENG −0.144508 \*\*\* −3.77031 \*\*\* 0.29438 \*\*\* 0.27416 \*\* GSC −3.268167 \*\*\* −15.37014 −2.16536 \*\*\* −3.29013 \*\* IMU 1.074738 \*\*\* 1.19463 \*\*\* 0.89635 \*\*\* 0.49992 \*\*\*

MTS −0.426886 \*\*\* −2.19212 \*\*\* 0.25507 \*\* 0.76189 \*\*\*

PLA −0.475982 \*\*\* −1.35393 \*\*\* −0.49401 \*\*\* −1.22287 \*\*\*

PSS −1.228774 \*\*\* −1.60205 −13.72792 −13.74086 SPA −4.640363 \*\*\* −15.22141 −13.74022 −13.82943 SSS −1.694540 \*\*\* −2.23959 \* −1.75911 . −13.78140

MAT −4.296640 \*\*\* −15.18047 −13.65028 −13.66243

MIC 0.829376 \*\*\* 0.31394 \* −0.71977 \* 0.29761 MOL 1.063727 \*\*\* 0.53478 \*\*\* 0.94839 NEB −0.22540 . −0.20025

PHT 0.402472 \*\*\* 0.71171 \*\*\* 0.19559 .

PHY −0.559729 \*\*\* −3.77438 \*\*\*

Signif. codes: "\*\*\*" 0.001, "\*\*" 0.01, "\*" 0.05, "." 0.1, ""1.

**Table 4.** Result of logistic regression of rate of patent-paper citations.

**Table 3.** Result of logistic regression analysis of patent feature values.

citations to distinguish it from other kinds of citations), and patent generality index. They are three of the four components of "composite index 4" presented in [8]. "Claims," which was the rest of the four, was not included in the study because it was not included in the Patstat comprehensively (only the US patents and European patents comprehensively included it exceptionally). As for "patent-patent forward citations," a dummy variable which distinguished whether patents obtained the top 1% of citations from other patents or not (it was presented as a "breakthrough" indicator in [8]) was used. The percentile of patent-patent citations was calculated by each of the 35 technology fields defined in [10].

Here, logistic regression analysis, of which independent variables were three patent feature values mentioned above, was executed. "Granted" flag in TLS201\_APPLN table in the Patstat was selected as dependent variable, since it should represent an aspect of patent quality. Please note that this analysis was executed in the initial stage of the study before the specification of dataset was decided; therefore, all types of patents (such as utility models) were included.

The results are shown in **Table 3**. All coefficients of the three independent variables were significant at 0.1 percent level. Two of them (patent family size and patent-patent forward citations) were positive, and the rest was negative. As far as grant of patents was regarded as representative of patent quality, the former represents some aspects of patent quality. Patent family size could be thought of as quality assessed by applicants themselves (self-assessed quality), since "applicants might be willing to accept additional costs and delays of extending protection to other countries only if they deem it worthwhile" (p. 14) [8], while patent-patent forward citations could be deemed as quality assessed mainly by other applicants or examiners. On the other hand, the patent generality index seemed not to represent patent quality in the aspect of patentability.
