Research Summary: Who is contributing to academic research on blockchain oracles? A bibliometric analysis

title: Research Summary - Who is contributing to academic research on blockchain oracles? A bibliometric analysis

description: The researcher does a bibliometric analysis of academic papers related to blockchain oracles. The researcher goes on to report the findings from the analysis to show the general trends in oracle publishing.

Tags: oracles, smart contracts, bibliometric analysis

created: 2021-09-08

researcher: Giulio Caldarelli -


  • The researcher took a broad sample of academic articles related to smart contracts, blockchains and oracles to investigate how oracles are being researched within academia.
  • The researcher found that although oracles are vitally important for connecting real-world data to smart contracts, research focusing on oracles specifically was lacking relative to other types of blockchain/smart contract-related research.
  • The researcher found that the publications he discovered came almost exclusively from within-university research, with only one inter-university publication out of the 111 papers analyzed.
  • The researcher observed a lack of collaboration worldwide, though authors and institutions were working in similar directions. On the other hand, most of the areas of research are poorly addressed while others remain uncovered.

Core Research Question

Which institutions and individuals contributed the most to research on blockchain oracles within academia?


Caldarelli G. Who Is Contributing to Academic Research on Blockchain Oracles? A Bibliometric Analysis.; 2021. DOI: 10.20944/preprints202109.0135.v1.

Who Is Contributing to Academic Research on Blockchain Oracles? A Bibliometric Analysis[v1] | Preprints


  • Blockchain Oracles:
    • Oracle Theory - This category includes papers specifically focused on blockchain oracles either from a theoretical or a practical point of view.
    • Oracle Applied - This category includes papers focused on real-world applications such as healthcare, finance, and business process management, providing a detailed analysis of the role of oracles in these fields with theoretical or experimental approaches.

Figure 1

The author uses a straightforward model of an oracle node as an intermediary aggregator between a data source and a smart contract.

  • Data Source: A specific data set, metadata set, database or metadata repository from which data or metadata are available.
  • Oracle Node: Each oracle node in a network evaluates another known node by two measures: action trust and recommendation trust.

Action trust refers to the probability that the evaluated node will perform the service or action with satisfactory quality for the evaluator.

Recommendation trust refers to the probability that the evaluated node will deliver correct recommendations about action trust of another node to the evaluator.

  • Smart Contract: A term used to describe computer code that automatically executes all or parts of an agreement and is stored on a blockchain-based platform.

Figure 2

The author defines a system in which a blockchain has an oracle cryptographically sign a transaction in addition to the transaction initiator, in order to establish a third party approval mechanism. The author uses Figure 2 to contextualize how oracles are implemented in systems without Turing-completeness.

Main categories are further divided into subcategories belonging to Oracle Theory:

  1. Architecture. With an empirical or theoretical approach, papers in this category perform analysis on the oracle framework to improve technical aspects, enlighten current challenges, and identify new avenues for research.

  2. Proposal. These papers propose new oracle frameworks that may be implemented

in real-world applications. Those may still be at a conceptual or prototype stage.

  1. Oracle Problem. Those articles focus on the aspects related to the trustworthiness of

oracles and their limits to decentralization.

Oracle Applied subcategories such as Healthcare and Supply Chain are

intuitive, those that require clarifications are described here:

  1. Data Management. Articles concerning the transfer of data from the real world to the blockchain are included in the Oracle Theory main category. This field considers articles that analyze the access data management for reputation, privacy, or GDPR purposes. Cloud Computing related researches will be filed under their own category since they mainly concern data elaboration.
  2. Finance. This category includes articles that involve oracles applied in financial applications and those exploring timeliness and gas usage of transactions. Those concerning asset management on the blockchain are also included.
  3. IoT. This category includes papers that investigate oracles as efficient IoT systems but do not refer to a specific real-world application. A paper concerning IoT in the supply chain, for example, would instead be inserted into the Supply Chain and Traceability category.


The researcher approached the subject with five questions as the starting point for his bibliometric analysis:

RQ1) Which institutions contributed more to the research on blockchain oracles? 

RQ2) Who are the most impactful authors in blockchain oracle research? 

RQ3) Which one is the most common publication type, outlet, and publisher? 

RQ4) Is there any existing cooperation among universities and scholars? 

RQ5) What is the most and the least investigated area?

One of the researcher’s main goals was to parse out research on Oracles without using a protocol-specific definition which would by proxy limit the scope of the literature.

Additionally, the “Oracle Software Company,” having a significant presence in the realm of networking, made it necessary for the author to actively exclude publications that were about case-studies of “Oracle Software.”

The researcher was aware that the definition of Oracles within the blockchain and smart contract space had a very specific connotation without a strict and accepted definition, and treated the bibliometric analysis as having a tentative definition of blockchain/smart contract oracles with non-exhaustive representation as a general example.

As there are not many real-world examples of applied oracles, the author wanted to make sure the study was not disproportionately weighted by the nascent nature of the industry-applied oracles.


  1. The researcher used the Scopus and Web of Science databases in addition to using Google Scholar for queries.

  2. The researcher included academic articles, but did not include white papers, opinion posts, or news articles.

  3. The researcher used Blockchain and Oracle as keywords in TITLE-ABS-KEY of Scopus database and identified 205 articles.

  4. Additional strings were added on the WoS database to yield 119 results.

  5. Google Scholar yielded more than 10,000 entries and the researcher decided to limit that to 300 articles using the top 30 pages of results.

  6. The researcher excluded papers that discussed “random oracles” or “test oracles” as those are not the same types of oracles that the researcher was searching for.

    Figure 3


Concerning contributions and metrics, it emerged that Xu Xiwei was the most impactful author in the field and has published the two most cited papers. Khalifa University, with 12 publications, is the most productive institution.

Figure 4

Oracle Architecture, Problem, and Proposal articles had the most publications within the subcategories of Oracle publications.

Figure 5

Additionally, the author highlighted the most common keywords associated with oracle publications and came up with the following categories: Architecture, Oracle Problem, Proposal, Finance, Data Management, IoT, BPM, Supply Chain & Traceability, AI, Cloud Computing, and Healthcare.

The aforementioned categories reflected the intersection of keywords searched and relevant articles returned, as the researcher used more keywords than those referenced in the results.

It should also be noted that the majority of the papers fall in the “Oracle Theory” category, as there is not a significant enough source of data to provide a balancing number of “Oracle Applied” publications.

The most cited papers came from a few select contributors:

Figure 6

China, the UAE, Italy and Germany were the countries with the highest number of Blockchain Oracle publications:

Figure 7

Discussion and Key Takeaways

  1. The researcher shows that a small number of researchers have a wide influence on Oracle Theory.
  2. Researchers like Xiwei Xu have a prolific record of publication and thus have great influence over the direction of theory within the Blockchain Oracle space.
  3. As conference papers have been heavily referenced, it is relevant to ensure that collaboration occurs between universities on conference papers.
  4. The research showed that while there was a significant amount of collaboration within universities, there was almost no between-university collaboration, with the researcher only finding one article of the 111 identified which contained between-university collaboration.


This work highlights the need for cooperation between universities to increase so that ideas are not needlessly retread. As there is an impetus to keep research private until it has been published, this article shows that there is a potential to accelerate the evolution of research on oracles by coordinating different schools to work on the same subject instead of having them siloed away from other research institutions.


This is a fascinating study that somewhat pulls the curtain open on how siloed academia is. However, is there some benefit to the silos as well? While there is certainly some retreading of the same ground, independent perspective on oracles might not be such a bad thing. One of the key takeaways here is that there are a small number of researchers influencing Oracle Theory currently. It strikes me that an inter-university collaboration model might make those ideas that much more influential and really solidify those perspectives into the literature. Isn’t there some benefit to non-aligned investigation of the same phenomenon?


I believe what you have alluded to is the potential for echo chambers to emerge within the inter-university collaborations. If I am interpreting your question correctly, I believe this is a legitimate concern that would be a logical benefit to isolated examination. On the one hand, there would seem to be a benefit to cooperation, but as you allude to; there is an inherent benefit to the siloed approach.
I know that an attempt to prevent plagiarism is one of the main reasons for the rigorous peer-reviewing that occurs during the publication process, and in that regard, the siloed approach to research does inherently prevent inter-university echo chambers and additionally creates an environment in which all of the ideas being put forth should have been screened for originality and value to the space.


This essentially got at the heart of my question. Coordination is important, but so is some independence. Independent researchers can help prevent the development of an influential orthodoxy, for lack of a better word.

That said, inter-university, and even bet yet, inter-organizational collaboration looks to be important here when I took a look back at Figure 5. I thought it was interesting that there seems to be some balance between Oracle Theory and Oracle Applied research, but there isn’t much balance within those categories. In particular, it is potentially concerning that Review as a research type is so underrepresented, especially in the Oracle Applied category. I need to do some digging to see how that categorization is working for these authors to determine if that really is a concern or not. Or perhaps I am needlessly concerned about what appears to be a methodological imbalance in the oracle research space?

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After some consideration, I believe this may be a theoretical conundrum that we have settled around. On the one hand, when you look at the search results for “bibliometric analysis” with the additional keywords of “blockchain” and “smart contracts,” there are 2,190 results yielded. So that trend would seem to indicate that there is at least some attempt to understand the distribution of works among the different areas of the smart contract academic publication space. On the other hand, unless a person looks across a representative sample of those bibliometric analyses; then it would be near impossible to know the scope of distribution of works in the space.

This may be one of those knowledge gaps that is perpetually in the process of being closed, but it can never philosophically be completely closed. Then further, is there an ideological need to have “balanced representation” in the research? It would be assumed that balanced research would be beneficial, but that may not be the reality of how things work in the real world. This particular bibliometric analysis has given me some new insight into how to look at the notion of “balance” in publication as obviously being a relative perspective, but whether that type of perceived balance is desirable or beneficial.


This is exploratory work, so it’s not really made to answer questions as much as to suggest them. Concerning RQ4, in particular, it does raise eyebrows, but I don’t think we can infer from the absence of cross-institution coauthorship that there is no cross-institutional research—it could be due to disciplinary culture around coauthorship and the way research is structured. I think checking citation networks would help.

@zube.paul “is there some benefit to the silos as well”: Yes. Ideas sometimes need to develop and mature before being thrown into the world where they will be scrutinized by those who might not share the same intuitions. I’ve seen it mostly in the context of marginalized groups (e.g. Fricker), but Lakatos makes a similar point about protecting budding theories from too harsh a judgment, to give them room to flourish first. Another point is that if researchers are in the same institution, they’re more likely to bump into each other and bounce ideas. There was a paper that suggested that research turned out more impactful when authors had their desk/office within 50m or 100m, but I can’t find it.

The idea, I think, is that there should be both spaces where teams can incubate their research and spaces where they can present it to a diverse audience for scrutiny.