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Participation Bias
Participation bias or non-response bias is a phenomenon in which the results of elections, studies, polls, etc. become non-representative because the participants disproportionately possess certain traits which affect the outcome. These traits mean the sample is systematically different from the target population, potentially resulting in biased estimates. For instance, a study found that those who refused to answer a survey on AIDS tended to be "older, attend church more often, are less likely to believe in the confidentiality of surveys, and have lower sexual self disclosure." It may occur due to several factors as outlined in Deming (1990). Non-response bias can be a problem in longitudinal research due to attrition during the study. Example If one selects a sample of 1000 managers in a field and polls them about their workload, the managers with a high workload may not answer the survey because they do not have enough time to answer it, and/or those with a low workload may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elections
An election is a formal group decision-making process by which a population chooses an individual or multiple individuals to hold public office. Elections have been the usual mechanism by which modern representative democracy has operated since the 17th century. Elections may fill offices in the legislature, sometimes in the executive and judiciary, and for regional and local government. This process is also used in many other private and business organisations, from clubs to voluntary associations and corporations. The global use of elections as a tool for selecting representatives in modern representative democracies is in contrast with the practice in the democratic archetype, ancient Athens, where the elections were considered an oligarchic institution and most political offices were filled using sortition, also known as allotment, by which officeholders were chosen by lot. Electoral reform describes the process of introducing fair electoral systems where they are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Research
Research is "creativity, creative and systematic work undertaken to increase the stock of knowledge". It involves the collection, organization and analysis of evidence to increase understanding of a topic, characterized by a particular attentiveness to controlling sources of bias and error. These activities are characterized by accounting and controlling for biases. A research project may be an expansion on past work in the field. To test the validity of instruments, procedures, or experiments, research may replicate elements of prior projects or the project as a whole. The primary purposes of basic research (as opposed to applied research) are documentation, Discovery (observation), discovery, interpretation (philosophy), interpretation, and the research and development (R&D) of methods and systems for the advancement of human knowledge. Approaches to research depend on epistemology, epistemologies, which vary considerably both within and between humanities and sciences. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opinion Poll
An opinion poll, often simply referred to as a survey or a poll (although strictly a poll is an actual election) is a human research survey of public opinion from a particular sample. Opinion polls are usually designed to represent the opinions of a population by conducting a series of questions and then extrapolating generalities in ratio or within confidence intervals. A person who conducts polls is referred to as a pollster. History The first known example of an opinion poll was a tallies of voter preferences reported on Telegram Messenger to the 1824 presidential election, showing Andrew Jackson leading John Quincy Adams by 335 votes to 169 in the contest for the United States Presidency. Since Jackson won the popular vote in that state and the whole country, such straw votes gradually became more popular, but they remained local, usually citywide phenomena. In 1916, ''The Literary Digest'' embarked on a national survey (partly as a circulation-raising exercise) and correc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AIDS
Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual may not notice any symptoms, or may experience a brief period of influenza-like illness. Typically, this is followed by a prolonged incubation period with no symptoms. If the infection progresses, it interferes more with the immune system, increasing the risk of developing common infections such as tuberculosis, as well as other opportunistic infections, and tumors which are rare in people who have normal immune function. These late symptoms of infection are referred to as acquired immunodeficiency syndrome (AIDS). This stage is often also associated with unintended weight loss. HIV is spread primarily by unprotected sex (including anal and vaginal sex), contaminated blood transfusions, hypodermic needles, and from mother to child duri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longitudinal Study
A longitudinal study (or longitudinal survey, or panel study) is a research design that involves repeated observations of the same variables (e.g., people) over short or long periods of time (i.e., uses longitudinal data). It is often a type of observational study, although it can also be structured as longitudinal randomized experiment. Longitudinal studies are often used in social-personality and clinical psychology, to study rapid fluctuations in behaviors, thoughts, and emotions from moment to moment or day to day; in developmental psychology, to study developmental trends across the life span; and in sociology, to study life events throughout lifetimes or generations; and in consumer research and political polling to study consumer trends. The reason for this is that, unlike cross-sectional studies, in which different individuals with the same characteristics are compared, longitudinal studies track the same people, and so the differences observed in those people are less like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Attrition Bias
Selection bias is the bias introduced by the selection of individuals, groups, or data for analysis in such a way that proper randomization is not achieved, thereby failing to ensure that the sample obtained is representative of the population intended to be analyzed. It is sometimes referred to as the selection effect. The phrase "selection bias" most often refers to the distortion of a statistical analysis, resulting from the method of collecting samples. If the selection bias is not taken into account, then some conclusions of the study may be false. Types Sampling bias Sampling bias is systematic error due to a non-random sample of a population, causing some members of the population to be less likely to be included than others, resulting in a biased sample, defined as a statistical sample of a population (or non-human factors) in which all participants are not equally balanced or objectively represented. It is mostly classified as a subtype of selection bias, sometimes spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1936 United States Presidential Election
The 1936 United States presidential election was the 38th quadrennial presidential election, held on Tuesday, November 3, 1936. In the midst of the Great Depression, incumbent Democratic President Franklin D. Roosevelt defeated Republican Governor Alf Landon of Kansas. Roosevelt won the highest share of the popular and electoral vote since the largely uncontested 1820 election. The sweeping victory consolidated the New Deal Coalition in control of the Fifth Party System. Roosevelt and Vice President John Nance Garner were re-nominated without opposition. With the backing of party leaders, Landon defeated progressive Senator William Borah at the 1936 Republican National Convention to win his party's presidential nomination. The populist Union Party nominated Congressman William Lemke for president. The election took place as the Great Depression entered its eighth year. Roosevelt was still working to push the provisions of his New Deal economic policy through Congress and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Literary Digest
''The Literary Digest'' was an influential American general interest weekly magazine published by Funk & Wagnalls. Founded by Isaac Kaufmann Funk in 1890, it eventually merged with two similar weekly magazines, ''Public Opinion'' and '' Current Opinion''. History Beginning with early issues, the emphasis was on opinion articles and an analysis of news events. Established as a weekly newsmagazine, it offered condensations of articles from American, Canadian and European publications. Type-only covers gave way to illustrated covers during the early 1900s. After Isaac Funk's death in 1912, Robert Joseph Cuddihy became the editor. In the 1920s, the covers carried full-color reproductions of famous paintings. By 1927, ''The Literary Digest'' climbed to a circulation of over one million. Covers of the final issues displayed various photographic and photo-montage techniques. In 1938, it merged with the ''Review of Reviews'', only to fail soon after. Its subscriber list was bought by ''T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Survey Sampling
In statistics, survey sampling describes the process of selecting a sample of elements from a target population to conduct a survey. The term "survey" may refer to many different types or techniques of observation. In survey sampling it most often involves a questionnaire used to measure the characteristics and/or attitudes of people. Different ways of contacting members of a sample once they have been selected is the subject of survey data collection. The purpose of sampling is to reduce the cost and/or the amount of work that it would take to survey the entire target population. A survey that measures the entire target population is called a census. A sample refers to a group or section of a population from which information is to be obtained Survey samples can be broadly divided into two types: probability samples and super samples. Probability-based samples implement a sampling plan with specified probabilities (perhaps adapted probabilities specified by an adaptive procedur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sampling Frame
In statistics, a sampling frame is the source material or device from which a sample is drawn. It is a list of all those within a population who can be sampled, and may include individuals, households or institutions. Importance of the sampling frame is stressed by Jessen and Salant and Dillman.Salant, Priscilla, and Don A. Dillman. "How to Conduct your own Survey: Leading professional give you proven techniques for getting reliable results" (1995) Obtaining and organizing a sampling frame In the most straightforward cases, such as when dealing with a batch of material from a production run, or using a census, it is possible to identify and measure every single item in the population and to include any one of them in our sample; this is known as ''direct element sampling''. However, in many other cases this is not possible; either because it is cost-prohibitive (reaching every citizen of a country) or impossible (reaching all humans alive). Having established the frame, there ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Response Rate (survey)
In survey research, response rate, also known as completion rate or return rate, is the number of people who answered the survey divided by the number of people in the sample. It is usually expressed in the form of a percentage. The term is also used in direct marketing to refer to the number of people who responded to an offer. The general consensus in academic surveys is to choose one of thsix definitions summarized by the American Association for Public Opinion Research(AAPOR). These definitions are endorsed by the National Research Council and the Journal of the American Medical Association, among other well recognized institutions. They are: # Response Rate 1 (RR1) – or the minimum response rate, is the number of complete interviews divided by the number of interviews (complete plus partial) plus the number of non-interviews (refusal and break-off plus non-contacts plus others) plus all cases of unknown eligibility (unknown if housing unit, plus unknown, other). # Response ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-selection Bias
In statistics, self-selection bias arises in any situation in which individuals select themselves into a group, causing a biased sample with nonprobability sampling. It is commonly used to describe situations where the characteristics of the people which cause them to select themselves in the group create abnormal or undesirable conditions in the group. It is closely related to the non-response bias, describing when the group of people responding has different responses than the group of people not responding. Self-selection bias is a major problem in research in sociology, psychology, economics and many other social sciences. In such fields, a poll suffering from such bias is termed a self-selected listener opinion poll or "SLOP". The term is also used in criminology to describe the process by which specific predispositions may lead an offender to choose a criminal career and lifestyle. While the effects of self-selection bias are closely related to those of selection bias, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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