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Topic: Observer bias

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	Cognitive bias - Wikipedia, the free encyclopedia
		Cognitive bias is any of a wide range of observer effects identified in cognitive science and social psychology including very basic statistical, social attribution, and memory errors that are common to all human beings.
		And biases related to probability and decision making significantly affect the scientific method which is deliberately designed to minimize such bias from any one observer.
		Bias arises from various life, loyalty and local risk and attention concerns that are difficult to separate or codify.
	en.wikipedia.org /wiki/Cognitive_bias (410 words)

	CHECKING THE ESSENTIALS
		Although there are procedures to help reduce observer bias, for example, by using automated recording equipment, or keeping observers “blind” to the goals of the study, perhaps the most important factor in dealing with it is being aware that observer bias might be present (and thus taking steps to reduce its effect).
		The observers recorded the gender of the observed person, the context in which the observation took place (e.g., how crowded it was, weather conditions), and the date and time of the observation.
		Observers reduced the likelihood of reactivity by positioning themselves so that they could see the passing and timing zones but so they would not be noticed by the people walking along the path.
	srv2.lycoming.edu /~kelley/expchapter4.htm (1918 words)

	Reducing Observer Bias in Pebble Counts
		All of the observers involved in the study obtained results that were significantly different from those of other observers for at least some size classes.
		The standard deviation for multiple observer measurements were larger, ranging from ±4.2 mm for 2 mm particles to ±64 mm for 300 mm particles.
		By comparing observer measurements done with a ruler with precise measurements done with a caliper, the study concludes that poor measurement technique plays a small role in biasing size estimates for some observers.
	www.stream.fs.fed.us /news/streamnt/jul96/jul96a1.htm (721 words)

	UPJ - UCLA Undergraduate Psychology Journal
		Furthermore, the actor-observer bias (Jones and Nisbett, 1972) indicates the significance of the target of evaluation during the process of attribution.
		Observers pay more attention to the actor in a situation, rather than the situational factors that may affect his or her behavior.
		Jones, E.E., and Nisbett, R.E. The actor and the observer: Divergent perceptions of the causes of behavior.
	www.studentgroups.ucla.edu /upj/fall2003/wingyunmak.html (3085 words)

	The Objective Observer (Site not responding. Last check: 2007-11-03)
		However, as The Objective Observer’s views and opinions are shaped purely by logic and are bound by The Objective Observer’s promise to fully explore and expound upon all arguments, Objective Observer cannot guarantee that some arguments and logical analysis will not offend some parties.
		While The Objective Observer meticulously researches all articles, articles are written to convey logical analysis and conclusions, not to rehash research that you should already be familiar with prior to reading The Objective Observer.
		Therefore, The Objective Observer does not footnote or otherwise document the research or the origin of facts that are of common historical record.
	theobjectiveobserver.com (551 words)

	Research in Education: Direct classroom observation
		Observer accuracy refers to the `extent to which observations scored by an observer match those of a predetermined standard for the same data' (often operationally identical to the concept of validity) (Kazdin, 1977, p.
		Observer bias, drift, and reactivity in those cases will be defined and evaluated, and ways will be suggested of controlling them.
		An example of observer bias is the case where an observer underestimates the amount and quality of the social interactions of a child with aggression problems.
	www.findarticles.com /p/articles/mi_qa3765/is_199805/ai_n8796397 (1292 words)

	1 (Site not responding. Last check: 2007-11-03)
		Observer calibration experiments (Gerrodette and Perrin, 1991) indicated that research vessel observer estimates of school size, given the true size, were approximately normal on the log scale, with constant variance.
		We treated the observer estimates (adjusted mean estimates in the case of research vessel data) as exact measurements, and did not attempt to correct for the possibility of size estimation biases in either data set (see Section) or use a deconvolution kernel to account for estimation variance.
		Both observer programs have extensive training, however, because of the large number that are needed, up to 15% of tuna vessel observers in the field are on their first cruise, while all of the research vessel observers had some previous experience.
	swfsc.ucsd.edu /PRD/dsweb/lj-97-03/lj-97-03.htm (13144 words)

	Cognitive bias - Open Encyclopedia (Site not responding. Last check: 2007-11-03)
		Cognitive bias is any of a wide range of observer effects identified in cognitive science, including very basic statistical and memory errors that are common to all human beings (first identified by Amos Tversky and Daniel Kahneman) and drastically skew the reliability of anecdotal and legal evidence.
		They also significantly affect the scientific method which is deliberately designed to minimize such bias from any one observer.
		Tversky and Kahneman claim that they are at least partially the result of problem-solving using heuristics, including the availability heuristic and the representativeness heuristic.
	open-encyclopedia.com /Cognitive_bias (125 words)

	six1 (Site not responding. Last check: 2007-11-03)
		In participant observation, the observer actually becomes a part of, a participant in, the situation to be observed.
		Observer bias refers to invalid observations that result from the way in which the observer observes.
		The other side of the coin is called the observer effect and refers to the impact of the observer's participation on the situation being observed.
	www.bsu.edu /classes/malone/id705/seven1.htm (2537 words)

	Gerard Keegan's Psychology Site: Glossary O
		Observer bias is an example of a confounding variable in observational research.
		Observer bias can occur in that the observer, and thus their results, may be influenced by prior knowledge, or experience of the situation / subject(s) / participant(s) under investigation.
		Observer effect is a confounding variable in observational research.
	www.gerardkeegan.co.uk /glossary/gloss_o.htm (760 words)

	Untitled Document (Site not responding. Last check: 2007-11-03)
		Observer variation in blood pressure measurement following training with standard techniques has been investigated in a study of 7735 middle-aged men.
		The magnitude of observer variation is in line with the few other published accounts, and is sufficient to have important implications for group comparisons, clinical trials, and the clinical care of individual patients.
		Four methods of reducing observer variation are considered: regular re-training, self-measurement and ambulatory monitoring, automatic sphygmomanometers, and adjustment in the analysis.
	www.chime.ucl.ac.uk /resources/student-projects/cer-2001-02/ll/8801.htm (185 words)

	How to Design and Evaluate Research in Education \| Main Points
		There are four roles that an observer can play in a qualitative research study, ranging from complete participant, to participant-as-observer, to observer-as-participant, to complete observer.
		The term "observer effect" refers to either the effect the presence of an observer can have on the behavior of the subjects or observer bias in the data reported.
		Observer bias refers to the possibility that certain characteristics or ideas of observers may affect what they observe.
	highered.mcgraw-hill.com /sites/0072532491/student_view0/chapter19/main_points.html (560 words)

	Issues in Psychological Measurement (Site not responding. Last check: 2007-11-03)
		Observer expectations, beliefs, etc. can influence their perceptions of that which they observe.
		This bias, by definition, eliminates objectivity from the measurement procedure; and, therefore, it is not acceptable in scientific inquiry.
		This holds for the beliefs of both the observer and the observed; the observer can be affected by them both.
	www.unc.edu /~nbearden/PSYC50/NOTES/MEASUREMENT2.htm (1322 words)

	Psychology Glossary by AlleyDog.com. Definitions of all the psychology terms you never understood before.
		Observer Bias: Observer bias is quite similar to Demand Characteristics except that the bias is with the "observers" of the research (i.e., the research team) rather than the participants.
		In other words, observer bias occurs when the observers (or researcher team) know the goals of the study or the hypotheses and allow this knowledge to influence their observations during the study.
		For example, if an observer knows that the researcher hypothesized that females speak in more complex sentences, they may believe they hear females speaking that way during the study even if it's not really true.
	www.alleydog.com /glossary/definition.cfm?term=Observer+Bias (201 words)

	On The Psychology of Watching Birds: The Problem of Observer-expectancy Bias
		Some observers were giv- en to believe that their planaria would move and turn frequently, whereas others expected their ani- mals to move and turn infrequently.
		When the reputation or research support of a researcher depends upon the outcome of the test of a hypothesis and he or she has taken no precautions against bias, the test may be nothing more than a self-fulfilling prophecy--a point occasionally made in the biological literature.
		One must wonder to what extent bias is respon- sible for the fact that relatively few "serious" hypotheses (as opposed to "straw" or "nuisance" hy- potheses) are rejected in the literature.
	elibrary.unm.edu /sora/Auk/v100n03/p0755-p0757.html (3105 words)

	Control of observer biases: masking (blinding) and placebos (Site not responding. Last check: 2007-11-03)
		Observer biases can be reduced and sometimes abolished by masked assessment (often referred to as blind assessment).
		The devices for masking assessments of treatment - when possible, using a placebo (dummy) treatment as part of the comparison - allow comparisons to be made which are independent of any observer bias or preconceived "knowledge".
		Masked assessment to reduce observer bias nevertheless remained on the margins of research in health care until random assignment of treatment groups gradually became accepted as the most effective method to avoid allocation bias in comparative trials during the second half of the 20th century.
	www.jameslindlibrary.org /essays/bias/kaptchuk.html (1509 words)

	FAE, AOB, SSB in Blast from the Past
		On the other hand, the actor-observer bias (AOB) assumes that the actor describes his or her own actions as a result of the situation, while the observer attributes the same actions as a stable personality traits to the actor (Aronson, 1999; Weiten and Lloyd, 2000).
		Adam makes the self-serving bias as he makes the excuse “I shouldn't be here this late.” He is using the situation to explain her change of attitude and his own failure to make her believe him.
		Eve, the observer, does not believe Adam's past and so she attributes his behavior to his personality that he is crazy.
	www.wiu.edu /users/muamt4/socbiases.html (1070 words)

	NEW TECHNIQUES FOR TIME-ACTIVITY STUDIES OF AVIAN FLOCKS IN VIEW-RESTRICTED HABITATS
		To begin sampling a flock, the observers estimated visually the number of individuals using major habitat types (e.g., upland field, forest canopy, willow thicket) and focal-units were distributed proportionately (Table 1).
		Radio-marked HY Mourn- ing Doves usually departed areas in small groups and often made sustained flights (>2 km) to their next area; hence, by the time the last focal-switch was made on a group leaving an area, the original focal bird probably was still in flight.
		However, problems of visibility bias arise in studies of species in dense habitats (Bradley 1985), because the investigator is confronted with sampling constraints that often cause data variability and biases (Kessel 1976, Verner 1965).
	elibrary.unm.edu /sora/JFO/v060n03/p0388-p0396.html (4627 words)

	Business Applications of Repertory Grid: Chapter 1
		Observer bias is a serious obstacle to understanding someone else's point of view, and it is not something that can be overcome with self-discipline and a tightening of resolve.
		Observer bias can have serious consequences, too; the most notable example may be that of the schoolteacher whose class was randomly split into two groups.
		Here the attraction was Grid's lack of observer bias: the technique of construct elicitation, which is central to the Grid process, can be used to tell you how the consumer views your products, and your competitors' products, without the distortion caused by intimate and specialised knowledge of the product.
	www.enquirewithin.co.nz /BUS_APP/busichap1.htm (3412 words)

	The Orange and Blue Observer: Liberal Bias in Speech Communication? (Site not responding. Last check: 2007-11-03)
		They continue to deny that bias exists even though there is abundant evidence through political campaign donations by professors, the overblown support of liberal causes through student organizations, and even the widespread liberal dominance in the Daily Illini.
		The bias in the Daily Illini is prominent throughout the whole issue concerning opinions and the way they frame events.
		The liberal bias is not very hard to find here at the University of Illinois, and one can even look in a simple Speech Communications book and find overwhelming bias in it.
	orangeandblueobserver.blogspot.com /2005/02/liberal-bias-in-speech-communication.html (723 words)

	Animal Behavior: Lizard Pushups (directory) (Site not responding. Last check: 2007-11-03)
		Along the way, the concepts of territoriality, types of questions in behavior research, observer bias, coding behavior, and the "dear enemy" phenomenon, are explained and illustrated.
		Observer bias: Introduces the problem of observer bias, with an illustration using an animated lizard.
		Observer bias and describing behavior: taking care in how you describe behavior is an important component of avoiding observer bias.
	eebweb.arizona.edu /Animal_Behavior/lizards/lizard_dir.htm (331 words)

	The NIJ Research Review (Site not responding. Last check: 2007-11-03)
		One key finding from the qualitative analysis was that the level of reactivity within observational data (in the form of social cues or explicit changes in patrol officer behavior) depended on the specificity of the data.
		Multivariate analyses were conducted to determine whether the qualitative coding or other potential sources of reactivity derived from the field research literature (i.e., observer sex, status congruency, and time in the field) were isolated instances or involved a systematic effect on patrol officer behavior in the form of significant effects within multivariate equations.
		Overall, the study indicates that reactivity could act as a systematic bias and mask or alter the true relationships between independent and dependent variables, leading to mistaken inferences being drawn from all studies that use observational data.
	www.ncjrs.org /rr/vol5_1/28.html (328 words)

	[No title]
		The result of information bias: Misclassification ¡65(¨BNondifferential misclassification Differential misclassification ¡CCª3ó¨%3.1 Nondifferential Misclassification¡&%(ª¨1Occurs when the degree of misclassification of exposure is independent of case-control status (vice-versa) Example: misclassification of HCV infection due to window period in a study looking at risk factors for HCV.
		Another example: In a cohort study of occupational exposures and asthma, the most susceptible individuals may be more likely to leave employment with early symptoms of asthma and the effect of the occupational exposure may be underestimated as a result.
		Selection bias can occur on the front end of a cohort study, by self- selection bias or by systematic error in recruitment.
	www.epibiostat.ucsf.edu /courses/schedule/epimethods/2001/Bias_atcr_2001.ppt (526 words)

	Bias [Oct 2000; 80-2]
		For the avoidance of doubt, the clinical bottom line is that wherever bias is found it results in a large over-estimation of the effect of treatments.
		Because of the large bias expected from studies which are not randomised or not blind, a scoring system [1] that is highly dependent on randomisation and blinding will also correlate with bias.
		That bias is present, and exists in so many different forms is why we have to be vigilant when reading about a clinical trial, and especially when taking the results of a single trial into clinical practice.
	www.jr2.ox.ac.uk /bandolier/band80/b80-2.html (2665 words)

	Categorical Data: Part 3: Plots for two-way frequency tables
		The observer agreement chart (Bangdiwala, 1987) provides a simple graphic representation of the strength of agreement in a contingency table, and a measure of strength of agreement with an intuitive interpretation.
		While special tests exist for marginal homogeneity, the observer agreement chart shows this directly by the relation of the dark squares to the diagonal line: When the marginal totals are the same, the squares fall along the diagonal.
		At issue is whether the data show evidence of sex bias in admission practices (Bickel et al., 1975).
	www.math.yorku.ca /SCS/Courses/grcat/grc3.html (2342 words)

	Observer Bias in Acellular Pertussis Vaccine Trials -- von König et al. 104 (3): 577 -- Pediatrics
		Observer Bias in Acellular Pertussis Vaccine Trials -- von König et al.
		The data from Cherry et al are an important warning that observer bias may be introduced into vaccine trials depending on
		Cherry JD, Heininger U, Stehr K, Christenson P The effect of investigator compliance (observer bias) on calculated efficacy in a pertussis vaccine trial.
	pediatrics.aappublications.org /cgi/content/full/104/3/577/a (663 words)

	Chapter 3 Summary
		If observer bias seems to be a problem, consider changing your measure (see table 3-1 on page 73 to learn how) or making observers "blind.
		Even if your measure is free from observer bias, it may not be free of subject bias.
		Bias is the most serious type of error a measure can have.
	psy1.clarion.edu /mm/RDClass/RDE4U/TC3/tsC3sum.html (692 words)

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