Reputation

= Reputation — as tokens, achievement markers, certifications and many more — is the primary information system that coordinate the flows of trust through the social sphere. [1]

Definition

"Reputation-based systems are used to establish trust among members of on-line communities where parties with no prior knowledge of each other use the feedback from their peers to assess the trust worthiness of the peers in the community." (http://whatifacomputerlies.blogspot.com/2007/04/reputation-system-in-p2p-network.html)

See also our entry on Reputation - Portability

Please note this important distinction by Tom Salfield: "I think its important to distinguish "currency" from a reputation measurement. Implicit in the term currency is the idea that it can be exchanged for something. A system for "recognition" is only a currency if that recognition is exchangable for something." (email, June 2010)

Description

From the Wikipedia:

"Reputation is the opinion (more technically, a social evaluation) of the public toward a person, a group of people, or an organization. It is an important factor in many fields, such as business, online communities or social status.

Reputation is known to be a ubiquitous, spontaneous and highly efficient mechanism of social control in natural societies. It is a subject of study in social, management and technological sciences. Its influence ranges from competitive settings, like markets, to cooperative ones, like firms, organisations, institutions and communities. Furthermore, reputation acts on different levels of agency, individual and supra-individual. At the supra-individual level, it concerns groups, communities, collectives and abstract social entities (such as firms, corporations, organizations, countries, cultures and even civilisations). It affects phenomena of different scale, from everyday life to relationships between nations. Reputation is a fundamental instrument of social order, based upon distributed, spontaneous social control." (http://en.wikipedia.org/wiki/Reputation)

From Michael Freedman et al:

"Reputation is a tool to predict behavior based on past actions and characteristics. We use reputation regularly in our daily lives --- reputations of individuals, as when we choose a physician; groups, as when we decide that individuals above a certain age can be trusted to purchase alcohol; and collective entities, as when we decide whether Ford is a company that will sell us good cars.

Reputation is based on linkability. When we can link actions to an identity, and link actions by that identity to other actions by that same identity, then we can begin to make predictions about the identity's future actions. We distinguish between the problem of verification (establishing identity and tying it to a real-world entity) and the problem of reputation (judging the behavior of a given identity). This chapter deals mainly with the latter, but we also tackle some of the problems with verification that impact reputation.

The concept of reputation, and the associated themes of building and assessing reputations, are not in themselves new ideas. Reputation, often signaled via a brand such as the New York Times, is an important concept in environments in which there is asymmetric information. Newspapers are a good example -- a reader must pay for the good before evaluating the good, and the seller and publisher likely have better information about the quality of the product. Without the ability to brand a product the newspaper market would likely spiral towards Akerlof's "Market for Lemons", with high quality products unable to differentiate themselves from low quality products and only low quality products surviving in the long-term. Reputation provides what Axelrod refers to as "the shadow of the future", with participants in a system considering the effect of current misbehavior on future interactions, even if future interactions are with different people. Reputation systems (systems that attempt to attach reputation to an identity and make an ongoing assessment of that reputation) promise to "unsqueeze the bitter lemon" (Resnick et al. 2000) by automating word-of-mouth reputation for electronic networks." (http://freehaven.net/~arma/jean.html)

Characteristics of Reputation

From: Manifesto for the Reputation Society by Hassan Masum and Yi–Cheng Zhang

URL = http://www.firstmonday.org/issues/issue9_7/masum/index.html

"Reputation is context–specific. A Ph.D. degree, medical license, or award of merit is meant to certify particular abilities. When a credit agency evaluates your financial history and generates a reputation, the context is your ability to repay loans; this ability may be correlated with but is quite distinct from more general character traits. And reputation could refer to any of these more general traits, like one’s sense of humor or ability to work in a team.

Since there is no absolute objective reputation quantity stamped on people’s foreheads, measurable proxies are necessary, such as book sales rankings, citations in academic papers, Web site visits, and readership of blogs. (Not coincidentally, they have similar highly asymmetric power–law distributions. Many distributions of wealth and of readership of non-electronic resources also follow power–law distributions, a fact noted in Zipf (1949) more than half a century ago.)

Reputation is a surrogate — a partial reflection representing our "best educated guess" of the underlying true state of affairs. Active evaluation by looking behind surface signals can corroborate or disprove reputations, while indiscriminate use degrades their reliability. The challenge is to encourage active evaluation, but also to use it efficiently since it will always be in limited supply.

Emerging information tools are making it possible for people to rate each other on a variety of traits, generating what is really a whole set of reputations for each person. (Information technology is also indirectly increasing the need for such reputations, as we have to sift through more and more possibilities.) You may mentally assign a friend a bad reputation for being on time or returning borrowed items promptly, while still thinking them reliable for helping out in case of real need. No person can be reduced to a single measure of "quality."

So people will have different reputations for different contexts. But even for the same context, people will often have different reputations as assessed by different judges. None of us is omniscient — we all bring our various weaknesses, tastes, bias, and lack of insight to bear when rating each other. And people and organizations often have hidden agendas, leading to consciously distorted opinions.

Reputations are rarely formed in isolation — we influence each others’ opinions. Studying the structure of social connectivity promises to reveal insights about how we interact, and thinking about simple quantities like the average number of sources consulted before an opinion is formed will help us to better filter these opinions.

Are reputations only for people? No, their scope is far wider:

• They can be for groups of people: companies, media sources, non–governmental organizations, fraternities, political movements.

• They are often used for inanimate objects: books, movies, music, academic papers, consumer products. Typically, whenever we talk about the "quality" of an object with some degree of subjectivity, we can also speak of its reputation, usually as assessed by multiple users — bestseller lists are a simple example.

• Finally, ideas can have reputations. Belief systems, theories, political ideas, and policy proposals are the bedrock of public discussion. The waxing and waning of idea–reputations directly affects their likelihood of implementation, and thus the environment that we all share

(http://www.firstmonday.org/issues/issue9_7/masum/index.html)

Design Characteristics

1. See Table 1 and 2 at http://www.firstmonday.org/issues/issue9_7/masum/index.html
2. The Reputation Design Pattern Library by Yahoo is stellar.

General Definition

From http://www.artsjournal.com/artfulmanager/main/005829.php:

"trust metric = an attempt to measure, assign, and convey trustworthiness among millions of strangers. As you might expect, most trust metrics work on two primary variables:

1) the evidence of your actions in the on-line space (the comments you post, the time you spend reading or participating, the transactions you complete, etc.) and

2) the assessment by other people of that evidence (did you say something smart, did you deliver the product you promised, or did you not, etc.)." (http://www.artsjournal.com/artfulmanager/main/005829.php)

Technical Definition

From the Open Privacy project:

"Reputation: A value that represents the collective opinion of some reference. A reputation is really just another name for an Opinion, as it is the calculated opinion of a Reference by the issuing Reputation Calculation Engine. Reputations are ephemeral, and the weight applied to an Opinion representing the reputation of some Reference is subjectively applied by the end user (person or program) that requests it. As Principals add their Opinion to a Reference, it accrues (positive or negative) reputation capital that has several useful properties:

Secure: Reputations cannot be subverted, and the source of reputation assertions can always be traced. This provides non-repudiation as well as the mechanism with which to decide which reputation information to trust.

Transitive: Reputations are transitive (within the constraints of a well-defined domain). For example, if A trusts B as a source of local news, and B trusts C for local news, then it could be determined that A trusts C for local news." (http://www.openprivacy.org/opd.shtml)

Important Design Considerations

"online reputation systems must consider several issues:

• How broad is the context we're trying to build a reputation for? Are we trying to predict how well a given person will perform at a very specific task (eg delivering a letter to the post office), or are we trying to predict his performance at a broad range of tasks such as delivering letters, running a company, and babysitting our kids?

• What's at stake? Are we talking about predicting whether he'll put a stamp on his envelope, or whether he'll betray our government's secrets?

• Can we tie people to their online identities, or is it possible for people to create many online identities that are not obviously related to each other?

• Assuming we've solved the issue of tying identities to real people, how can we measure reputation?

• Finally, what algorithms can let us make accurate predictions based on these reputation values?"

(http://freehaven.net/~arma/jean.html)

Reputation in P2P Systems

"Generally the reputation system in P2P network follows four steps.

Step 1: a requestor r locates available resources sending a broadcast Query message to ask for the files it needs to download. Other peers will answer with a QueryHit message to the requesting node to notify that they have the requested resource.

Step 2: Upon receiving a set of QueryHit messages, r selects an offerer o and polls the community for any available reputation information on o sending a Poll message. As a result of step 2, r receives a set V of votes, some of which express a good opinion while others express a bad one.

step 3: revaluates the votes to collapse any set of votes that may belong to a clique and explicitly selects a random set of votes for verifying their trustworthiness.

step 4: the set of reputations collected in step 3 is computed into an aggregated community-wide reputation value. Base on this reputation value, the requestor r can take a decision on whether accessing the resource offered by o or not.After accessing the resource r can update its local trust on o (depending on whether the downloaded resource was satisfactory of not)." (http://whatifacomputerlies.blogspot.com/2007/04/reputation-system-in-p2p-network.html)

Examples of Reputation Systems

See also our entry on Trust Metrics

Applications

From: Manifesto for the Reputation Society by Hassan Masum and Yi–Cheng Zhang

URL = http://www.firstmonday.org/issues/issue9_7/masum/index.html

"The process of filtering information to distill a smaller yet more refined set of usable, verified, trustworthy judgements is not easy. But it is doable. And it is both more feasible and more necessary now than ever before, due to information proliferation, technological advances, and pressing socio–economic problems. Indeed, we already see many types of reputation systems emerging, especially online:

• Slashdot has grown to be a prime tech news site largely because of its inspired combination of open contribution and bottom–up filtering, using a modest amount of effort distributed over a large number of people — ranking the thousands of daily comments so one can choose to read just a few gems or all contributions. Similar communities are arising with different focuses, and figuring out why some fail while others succeed will teach us valuable design lessons.

URL = http://slashdot.org/moderation.shtml

• Amazon, the online bookselling pioneer that has grown to be a juggernaut, early on made a decision to let users themselves rate each item, optionally accompanied by comments. Browsing through these ratings, suggestions, and warnings can be a gold mine of useful tips, one that is hard to replicate.

• eBay uses reputations at the heart of its online auction system, for ranking buyer and seller honesty. Without this feedback, weeding out the bad apples who renege on deals would be far more difficult.

URL = http://pages.ebay.com/help/feedback/evaluating-feedback.html

• Google uses derived reputations from Web page interlinking to decide which search results are most relevant, which proved so effective that it has rapidly grown to become a global information utility. It has no "community boundaries," but extends use of reputation to the Web in its entirety.

• BizRate and ePinions provide ratings of businesses, seeking to identify those with better product quality and customer service. Both depend on feedback from many consumers, summarizing the experiences of many and in turn influencing future purchasing decisions of consumers in a virtuous feedback loop."

(http://www.firstmonday.org/issues/issue9_7/masum/index.html)

Other examples:

- The Flickr interestingness algorhythm at http://www.flickr.com/explore/interesting/

Dedicated Reputation Systems

Overview of online reputation management tools at http://www.readwriteweb.com/archives/how_to_manage_your_online_reputation.php

1. iKarma
2. Rapleaf
3. Bazaar Voice
4. Venyo
5. The Gorb
6. Opinity
7. Co-workers

Reputation Systems specific to Second Life

1. TrustNet
2. BanLink

(Brand) Reputation Monitoring and Management Systems

1. 10 Brand Reputation Monitoring Systems reviewed at

http://mashable.com/2008/12/29/brand-reputation-monitoring-tools/

P2PRep

"P2PRep is a reputation-based protocol runs in a completely anonymous P2P networks. In P2PReP, local reputation management and community-wide reputation management are two different levels. Local reputation is defined as one single peer’s opinion of one other peer’s reputation, based on its formal experience. The community reputation means the aggregated general opinion given by multiple peers. P2PRep is generally combine these two factors together.

P2Prep works well in the environments of the percentage of malicious peers’ increasing and decreasing by changing well-behaved ones to rogues ones and changing rogue ones into well-behaved ones. As to the turn over case in peers’ population, P2PReP confirms its robust-ness showing a percentage of malicious downloads greater about 1% than scenario with no change." (http://whatifacomputerlies.blogspot.com/2007/04/reputation-system-in-p2p-network.html)

Discussion

Why Reputation is Important

John H. Clippinger on Identity, Reputation, and Social Currency

"Rating and reputation system are a natural and universal artifact of all forms of human cooperation.

Reputation systems are an especially important aspect of social cooperation because they are attached to an individual and form the basis for whether they can be trusted and accepted. A reputation is really the collection of tags that are assigned to an individual or entity to reflect assessments of their competence or status within a specific social network. Given that individuals play different roles in social networks - they can serve variously as connectors, gatekeepers, truth-tellers and enforcers - reputations are tied to roles within social networks.

In eBay, for example, a seller acquires a reputation score given to them by their buyers. Different reputation score levels not only make it more likely that others will do business with them, but it confers a certain status among other members of the eBay community. To encourage participation, many online games depend upon accumulated scores, levels, roles and ratings of players. So do many peer production undertakings such as Wikipedia, Slashdot and open source software development.

Reputation systems are, in fact, linked to all aspects of human endeavor - sports with its performance statistics, education with its grades and degrees, social standard with its board and club memberships. Credit scores are a familiar type of reputation system that is now integral not only to receiving credit, but to participating in society and the economy at large. Credit scores are based upon financial behaviors that are thought to predict the likelihood of default or late payment.

It is not difficult to see how important reputation tags are in small traditional societies where once a reputation is acquired, it may be very difficult to change. Honor-based societies depend upon reputation tags as the principal governance mechanism for defining and enforcing a social order. "Honor killings" of a daughter or sister in order to preserve a familiar reputation suggest the power of reputation in Human Nature. Even in online communities, reputation tags are the motivator and governor of behaviors. People take seriously the reputation scores of an eBay seller/buyer, the accumulated scores of a player of online games, or the number of friends and ratings one has in the online social networks of Linkedin, Orkut, Friendster, Facebook, or My Space.

Identity is not something that can be self-defined. It is granted and modulated by one's roles, relationships, and reputations in a variety of social networks. One's identity (whether it be an individual person, group or organization) is closely tied to reputation tags and roles in social networks. How you see yourself depends upon how other see and rate you.

Reputation tags affect an individual or group's ability to participate within and across different networks, thereby becoming the basis for granting/revoking certain privilege and decision rights. Since reputation tags can be measures of competence by a socially credible third party - e.g., religious, educational, financial, political, trade or professional institutions - they play a very powerful role in governing social mobility and enabling/thwarting interactions between different social networks. By providing information about information - who or what it is, where it came from, as well as marking the rights and privileges for accessing, exchanging, altering, or forwarding goods, services and information, tags are the true control points in self-organizing networks." (http://onthecommons.org/node/723)

See what John Clippinger has to say on Social Currencies, from the same essay.

Why Reputation may be less important online

Judith Donath:

"Reputation is central to community formation and cooperation (Emler 2001; Gluckman 1963; Hardin 2003). Through discussion about others’ actions, people establish and learn about the community’s standards. Reputation is the core of rewards and sanctioning – it amplifies the benefits of behaving well and the costs of misbehavior. If I work with someone who turns out to be lazy and dishonest, by telling my friends about it, they are spared from a similar bad experience. Having access to reputation information is a big benefit of community membership: insiders know who to trust and how to act toward each other, while strangers do not get the benefit of other’s past experiences. Our ability to share reputation information makes society possible (Dunbar 1996).

In light of this, it would seem that the answer to the question “Is reputation obsolete?” is “No”.

Yet reputation is subject to manipulation, for various reasons. People use it to influence opinion to advance their own causes, to maliciously harm someone, or to curry favor by providing entertaining or seemingly confidential material. We need to understand what circumstances make reputation reliable.

Reputation information exchanged within close-knit communities is more reliable, and members learn when assessments are biased. A colleague recently mentioned that she would never trust another recommendation letter from Professor X again – she’d seen too many in which he claimed that different students were “the top scholar I’ve known”. In overzealously promoting the careers of his students, Professor X acquired a poor reputation for inflated praising. Most letter writers temper the desire to over-enthusiastically praise in order to remain credible in the eyes of their peers, realizing that this close-knit community assesses the assessors. Without community ties, reputation is generally less useful. On public rating sites such as eBay, where no community binds the rater and the reader of ratings, there is no check on reliability and the ratings function primarily as a social exchange between the rater and subject (David & Pinch 2006).

So, is reputation obsolete in an increasingly archival world? The answer, it appears, is “sometimes”. When the immediate facts are primary, we should make use of the vast amount of archived material available. But when situations are ambiguous, when there are conflicting versions of events or codes of behavior, and when developing a shared culture is important (Merry 1997), reputation and the communicative, community-building process of creating it is far from obsolete.

Online, new factors affect the balance between reputation and history. One big issue is “portable identity”: if I spend countless hours on a site being a gracious and well-informed companion, shouldn’t I be able to take that personal history and reputation with me to another site? Many would argue yes, that “you own your own words”. (More controversial is the question of whether you *must* take your history with you: people prefer to port only positive pasts.) But porting reputation is a different matter. Your reputation is information about you, but it is not by you. If you own your own words, then your reputation is owned not by you, but by the people who talk about you. Furthermore, it is a subjective judgment made it a specific context that may not translate well into another. History is portable in ways that reputation is not.

An online site can encourage reliance on history by making search easy and by providing visualizations of patterns within its archive. Or it can encourage the use of reputation by providing both public and private communication channels, as well as feedback about the value of the reputation information people have provided. In technologically mediated societies, evaluating the relative merits of history and reputation is especially important, for the habits of such communities are shaped by deliberate design." (http://publius.cc/2008/10/17/donath-is-reputation-obsolete/)

Reputation is not a collective right

Peter St. Andre argues that reputation is not socially constructed, not tied to collective rights over the individual, but an emergent property of the network:

"It is true that all individuals who wish to productively interact within a community benefit from the existence of reputation as a signalling mechanism; but that does not mean that reputation is a matter of collective interest or group belonging. Reputational signals are used always by individuals within a community and make it easier for those individuals to decide with whom to interact. Thus the benefits of reputational effects are dispersed among all members of the community. But it is a serious error of reification to therefore conclude that the group or community or collective realizes benefits, possesses rights, or pursues actions.

Consider again the analogy to prices. The emergence of prices from economic transactions between buyers and sellers benefits all members of the economic community that is concerned with the product or service at hand (and even members of economic communities concerned with other classes of goods and services, whose prices in turn are affected by the prices of goods and services in the first community). But prices are not therefore the property of all the economic actors in that community, they are not a collective creation of the community, and the group does not have rights to those prices. The same is true of reputation, and it is critically important to recognize the emergent nature of reputation if we are not to be led astray into notions of collective rights that will be inimical to individual participation in online communities." (https://stpeter.im/?p=1427)

For a counter-argument see Beth Noveck's Creating a Legal Framework for Online Identity.

How the Internet changed Reputation Systems

Lucio Picci [2]:

"In this respect, the Internet innovates in three important ways, by allowing what Dellarocas (2003) defines the word–of–mouth.”

First, it allows to spread voice–of–mouth to an unprecedented level. This, in turn, permits the existence of reputation–based interactions — be them of the market type, or other — at a global level and among persons many degrees of separation apart.

Secondly, the presence of a digital information infrastructure allows for a careful engineering of many details that contribute to the overall outcome of the system, such as: The condition under which the assessments are made, the metric according to which they aggregate to form a reputation index, the rules for participating and the possibility of changing one’s identity, etc.

Third, the Internet democratizes reputation systems, because it allows for their design so that all relevant parties may play the game under similar conditions. In conventional contexts information on reputation mostly spreads informally and via social networks: people who are better placed within them are at an advantage because they obtain better information. This, in turn, creates an incentive to spend time and resources to place oneself within such advantaged networks, a socially wasteful activity that economists would define as “rent seeking”." (http://www.firstmonday.org/issues/issue12_9/picci/index.html)

More Informaton

• on the relationship between money and reputation as different form of 'currencies': http://reputationcurrents.com/blog/archives/7
• Negative feedback reputation systems have been shown mathematically to always spiral into chaos [3]

Also:

1. Insightfull commentary by Clay Shirky at

[4]

1. See also our entries on Reputation - Portability and Reputation-based Governance
2. Extensive Wikipedia article at http://en.wikipedia.org/wiki/Reputation
3. See also our entries on Trust and Identity
4. Reputation in Open Source. Andrew Watson.
5. Typology of Reputation Currencies at http://newcurrencyfrontiers.blogspot.com/2009/04/reputations.html

Key Books to Read

The Reputation Society, forthcoming book by by Hassan Masum and Yi–Cheng Zhang

URL = http://reputationsociety.com/