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Three Degrees Of Influence
Three Degrees of Influence is a theory in the realm of social networks, proposed by Nicholas A. Christakis and James H. Fowler in 2007. It has since been explored by scientists in numerous disciplines using diverse statistical, psychological, sociological, and biological approaches. Christakis and Fowler explored the influence of social connections on behavior. They described how social influence does not end with the people to whom a person is directly connected. People influence their friends, who in turn influence their friends, and so on; hence, a person's beliefs and actions can influence people they have never met, to whom they are only indirectly tied. Christakis and Fowler posited that diverse phenomena "ripple through our network, having an impact on our friends (one degree), our friends’ friends (two degrees), and even our friends’ friends’ friends (three degrees). Our influence gradually dissipates and ceases to have a noticeable effect on people beyond the social fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Social Network
A social network is a social structure made up of a set of social actors (such as individuals or organizations), sets of dyadic ties, and other social interactions between actors. The social network perspective provides a set of methods for analyzing the structure of whole social entities as well as a variety of theories explaining the patterns observed in these structures. The study of these structures uses social network analysis to identify local and global patterns, locate influential entities, and examine network dynamics. Social networks and the analysis of them is an inherently interdisciplinary academic field which emerged from social psychology, sociology, statistics, and graph theory. Georg Simmel authored early structural theories in sociology emphasizing the dynamics of triads and "web of group affiliations". Jacob Moreno is credited with developing the first sociograms in the 1930s to study interpersonal relationships. These approaches were mathematically for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Randomized Controlled Trial
A randomized controlled trial (or randomized control trial; RCT) is a form of scientific experiment used to control factors not under direct experimental control. Examples of RCTs are clinical trials that compare the effects of drugs, surgical techniques, medical devices, diagnostic procedures or other medical treatments. Participants who enroll in RCTs differ from one another in known and unknown ways that can influence study outcomes, and yet cannot be directly controlled. By randomly allocating participants among compared treatments, an RCT enables ''statistical control'' over these influences. Provided it is designed well, conducted properly, and enrolls enough participants, an RCT may achieve sufficient control over these confounding factors to deliver a useful comparison of the treatments studied. Definition and examples An RCT in clinical research typically compares a proposed new treatment against an existing standard of care; these are then termed the 'experime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Six Degrees Of Separation
Six degrees of separation is the idea that all people are six or fewer social connections away from each other. As a result, a chain of " friend of a friend" statements can be made to connect any two people in a maximum of six steps. It is also known as the six handshakes rule. The concept was originally set out in a 1929 short story by Frigyes Karinthy, where a group of people play a game trying to connect any person in the world to themselves by a chain of five others. It was popularized in John Guare's 1990 play '' Six Degrees of Separation''. The idea is sometimes generalized to the average social distance being logarithmic in the size of the population. Early conceptions Shrinking world Theories on optimal design of cities, city traffic flows, neighborhoods, and demographics were in vogue after World War I. These conjectures were expanded in 1929 by Hungarian author Frigyes Karinthy, who published a volume of short stories titled ''Everything is Different.'' One o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mark Granovetter
Mark Sanford Granovetter (; born October 20, 1943) is an American sociologist and professor at Stanford University. He is best known for his work in social network theory and in economic sociology, particularly his theory on the spread of information in social networks known as ''The Strength of Weak Ties'' (1973). In 2014 Granovetter was named a Citation Laureate by Thomson Reuters and added to that organization’s list of predicted Nobel Prize winners in economics. Data from the Web of Science show that Granovetter has written both the first and third most cited sociology articles. Education Granovetter earned an Bachelor of Arts degree in history at Princeton University (1965) and a PhD in sociology at Harvard University (1970). At Harvard his research was supervised by Harrison White. Career and research Granovetter is currently the Joan Butler Ford Professor in the School of Humanities and Sciences at Stanford and is the chair of the Department of Sociology. He previ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Economics
Economics () is the social science that studies the production, distribution, and consumption of goods and services. Economics focuses on the behaviour and interactions of economic agents and how economies work. Microeconomics analyzes what's viewed as basic elements in the economy, including individual agents and markets, their interactions, and the outcomes of interactions. Individual agents may include, for example, households, firms, buyers, and sellers. Macroeconomics analyzes the economy as a system where production, consumption, saving, and investment interact, and factors affecting it: employment of the resources of labour, capital, and land, currency inflation, economic growth, and public policies that have impact on these elements. Other broad distinctions within economics include those between positive economics, describing "what is", and normative economics, advocating "what ought to be"; between economic theory and applied economics; between ratio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Public Health
Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the determinants of health of a population and the threats it faces is the basis for public health. The ''public'' can be as small as a handful of people or as large as a village or an entire city; in the case of a pandemic it may encompass several continents. The concept of ''health'' takes into account physical, psychological, and social well-being.What is the WHO definition of health? from the Preamble to the Constitution of WHO as adopted by the International Health Conference, New York, 19 June - 22 July 1946; signed on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Public Policy
Public policy is an institutionalized proposal or a decided set of elements like laws, regulations, guidelines, and actions to solve or address relevant and real-world problems, guided by a conception and often implemented by programs. Public policy can be considered to be the sum of government direct and indirect activities and has been conceptualized in a variety of ways. They are created and/or enacted on behalf of the public typically by a government. Sometimes they are made by nonprofit organisations or are made in co-production with communities or citizens, which can include potential experts, scientists, engineers and stakeholders or scientific data, or sometimes use some of their results. They are typically made by policy-makers affiliated with (in democratic polities) currently elected politicians. Therefore, the "policy process is a complex political process in which there are many actors: elected politicians, political party leaders, pressure groups, civil serva ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Society
A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group sharing the same spatial or social territory, typically subject to the same Politics, political authority and dominant cultural expectations. Societies are characterized by patterns of relationships (social relations) between individuals who share a distinctive culture and institutions; a given society may be described as the sum total of such relationships among its constituent of members. In the social sciences, a larger society often exhibits social stratification, stratification or dominance hierarchy, dominance patterns in subgroups. Societies construct patterns of behavior by deeming certain actions or concepts as acceptable or unacceptable. These patterns of behavior within a given society are known as societal norms. Societies, and their norms, undergo gradual and perpetual changes. Insofar as it is collaborative, a society can enable i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Will
Free will is the capacity of agents to choose between different possible courses of action unimpeded. Free will is closely linked to the concepts of moral responsibility, praise, culpability, sin, and other judgements which apply only to actions that are freely chosen. It is also connected with the concepts of advice, persuasion, deliberation, and prohibition. Traditionally, only actions that are freely willed are seen as deserving credit or blame. Whether free will exists, what it is and the implications of whether it exists or not are some of the longest running debates of philosophy and religion. Some conceive of free will as the right to act outside of external influences or wishes. Some conceive free will to be the capacity to make choices undetermined by past events. Determinism suggests that only one course of events is possible, which is inconsistent with a libertarian model of free will. Ancient Greek philosophy identified this issue, which remains a major fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resampling (statistics)
In statistics, resampling is the creation of new samples based on one observed sample. Resampling methods are: # Permutation tests (also re-randomization tests) # Bootstrapping # Cross validation Permutation tests Permutation tests rely on resampling the original data assuming the null hypothesis. Based on the resampled data it can be concluded how likely the original data is to occur under the null hypothesis. Bootstrap Bootstrapping is a statistical method for estimating the sampling distribution of an estimator by sampling with replacement from the original sample, most often with the purpose of deriving robust estimates of standard errors and confidence intervals of a population parameter like a mean, median, proportion, odds ratio, correlation coefficient or regression coefficient. It has been called the plug-in principle,Logan, J. David and Wolesensky, Willian R. Mathematical methods in biology. Pure and Applied Mathematics: a Wiley-interscience Series of Texts, M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicholas A
Nicholas is a male given name and a surname. The Eastern Orthodox Church, the Roman Catholic Church, and the Anglican Churches celebrate Saint Nicholas every year on December 6, which is the name day for "Nicholas". In Greece, the name and its derivatives are especially popular in maritime regions, as St. Nicholas is considered the protector saint of seafarers. Origins The name is derived from the Greek name Νικόλαος (''Nikolaos''), understood to mean 'victory of the people', being a compound of νίκη ''nikē'' 'victory' and λαός ''laos'' 'people'.. An ancient paretymology of the latter is that originates from λᾶς ''las'' ( contracted form of λᾶας ''laas'') meaning 'stone' or 'rock', as in Greek mythology, Deucalion and Pyrrha recreated the people after they had vanished in a catastrophic deluge, by throwing stones behind their shoulders while they kept marching on. The name became popular through Saint Nicholas, Bishop of Myra in Lycia, the inspirati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propensity Score Matching
In the statistical analysis of observational data, propensity score matching (PSM) is a statistical matching technique that attempts to estimate the effect of a treatment, policy, or other intervention by accounting for the covariates that predict receiving the treatment. PSM attempts to reduce the bias due to confounding variables that could be found in an estimate of the treatment effect obtained from simply comparing outcomes among units that received the treatment versus those that did not. Paul R. Rosenbaum and Donald Rubin introduced the technique in 1983. The possibility of bias arises because a difference in the treatment outcome (such as the average treatment effect) between treated and untreated groups may be caused by a factor that predicts treatment rather than the treatment itself. In randomized experiments, the randomization enables unbiased estimation of treatment effects; for each covariate, randomization implies that treatment-groups will be balanced on ave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
