## 4 Results and Discussion
### Which part of the patent document are widely used for prior art searches? Patents are intricate legal and technical documents, incorporating a blend of technical terminologies, legal jargon, and specialized acronyms. A patent document consists of several component sections, each serving a specific purpose and holding a different level of significance. Table S7 in Section S3.4 of the Supplementary Materials delineates the various components of a patent document, detailing their specific functions and providing explanations to enhance understanding of their roles within the overall structure of a patent. Several studies have used complete patent documents, while others have utilized combinations of different sections, or in some cases, a single section of the patent document to retrieve patents of interest. Figure 7 summarizes the findings of the survey. A total of 14 studies have used the whole patent document to aid in the patent retrieval process, while 12 studies have utilized the title, abstract, claims, and description sections of the patent document to perform prior art and other searches. The abstract and title are also a popular combination reported to have been used by seven studies. Some studies [122; 60] have made use of the title only to perform their searches. However, a total of eight studies did not specify the part of the patent document they used to perform prior art searches. Figure 6: Utilization of semantic search and natural language processing for the patent retrieval process. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**NLP Model** & **Type** & **Number of Studies** & **Embedding** & **Study** \\ \hline \multirow{4}{*}{**Tools**} & Stanford CoreNLP & 1 & Word Embeddings & [89] \\ \cline{2-4}  & OpenNLP & 1 & [90] \\ \cline{2-4}  & NS & 1 & [115] \\ \cline{2-4}  & TreeTagger & 2 & [91; 99] \\ \hline
**Topic Modelling** & & 2 & [61; 66] \\ \hline
**Unigram language model** & & 2 & [82; 39] \\ \hline
**Word2 vec** & & 5 & Word Embeddings & [67; 72; 73; 74; 75; 76; 77; 78; 79; 80; 81; 82; 83; 84; 85; 86; 87; 88; 89; 82; 84; 86; 87; 88; 89; 80; 83; 85; 84; 87; 88; 89; 85; 86; 88; 87; 89; 80; 84; 88; 89; 8  
The preference for using full patent documents to assess the patent retrieval systems may enable a thorough grasp of the context, tackle varying levels of detail, and understand the full scope and its implications, but this requires a greater amount of time and resources. On the other hand, using specific parts of the patent documents, such as abstracts, claims, descriptions, or titles to train and evaluate a patent retrieval system is an efficient and effective way to comprehend and make use of the important information contained in the patent documents, as they offer relevance by focusing on crucial details about the invention. This method also makes system evaluation and initial relevance ranking faster. Nevertheless, selective use may overlook the contextual depth and crucial information found in full patent documents. Therefore, there should be a smart selection of specific parts of the patent documents to evaluate the retrieval systems that strike a balance between efficiency and comprehensiveness. Claims (legal scope), abstracts (concise summary), titles (short explanation of subject matter), descriptions (detailed technical information), and citations (intellectual lineage) are the sections of patent documents that can be most relevant for evaluating retrieval system performance, by considering both technical details and intellectual context. Classification systems like the International Patent Classification (IPC) and the Cooperative Patent Classification (CPC) greatly improve patent searches by offering a standardized framework for classifying and extracting patent documents according to specific technological domains. The IPC, managed by WIPO, is used globally and involves a broad classification into sections, classes, subclasses, groups, and subgroups.