Personal equation
Encyclopedia
The personal equation, in 19th- and early 20th-century science
, referred to the idea that every individual observer had an inherent bias
when it came to measurement
s and observation
s.
The term originated in astronomy
, when it was discovered that numerous observers making the simultaneous observations would record slightly different values (for example, in recording the exact time at which a star
crossed a wire in a telescope
view-finder), some of which were of a significant enough difference to afford for problems in larger calculations.
In response to this realization, astronomers became increasingly suspicious of the results of other astronomers and their own assistants, and began systematic programs to attempt to find ways to remove or lessen the effects. These included attempts at the automation of observations (appealing to the presumed objectivity
of machines), training observers to try to avoid certain known errors (such as those caused by lack of sleep
), developing machines which could allow multiple observers to make observations at the same time, the taking of redundant data and using techniques such as the method of least squares to derive possible values from them, and trying to quantify the biases of individual workers so that they could be subtracted from the data. It became a major topic in experimental psychology
as well, and was a major motivation for developing methods to deal with error
in astronomy.
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...
, referred to the idea that every individual observer had an inherent bias
Bias
Bias is an inclination to present or hold a partial perspective at the expense of alternatives. Bias can come in many forms.-In judgement and decision making:...
when it came to measurement
Measurement
Measurement is the process or the result of determining the ratio of a physical quantity, such as a length, time, temperature etc., to a unit of measurement, such as the metre, second or degree Celsius...
s and observation
Observation
Observation is either an activity of a living being, such as a human, consisting of receiving knowledge of the outside world through the senses, or the recording of data using scientific instruments. The term may also refer to any data collected during this activity...
s.
The term originated in astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
, when it was discovered that numerous observers making the simultaneous observations would record slightly different values (for example, in recording the exact time at which a star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
crossed a wire in a telescope
Telescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
view-finder), some of which were of a significant enough difference to afford for problems in larger calculations.
In response to this realization, astronomers became increasingly suspicious of the results of other astronomers and their own assistants, and began systematic programs to attempt to find ways to remove or lessen the effects. These included attempts at the automation of observations (appealing to the presumed objectivity
Objectivity (science)
Objectivity in science is a value that informs how science is practiced and how scientific truths are created. It is the idea that scientists, in attempting to uncover truths about the natural world, must aspire to eliminate personal biases, a priori commitments, emotional involvement, etc...
of machines), training observers to try to avoid certain known errors (such as those caused by lack of sleep
Sleep
Sleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and is more easily reversible than...
), developing machines which could allow multiple observers to make observations at the same time, the taking of redundant data and using techniques such as the method of least squares to derive possible values from them, and trying to quantify the biases of individual workers so that they could be subtracted from the data. It became a major topic in experimental psychology
Experimental psychology
Experimental psychology is a methodological approach, rather than a subject, and encompasses varied fields within psychology. Experimental psychologists have traditionally conducted research, published articles, and taught classes on neuroscience, developmental psychology, sensation, perception,...
as well, and was a major motivation for developing methods to deal with error
Error
The word error entails different meanings and usages relative to how it is conceptually applied. The concrete meaning of the Latin word "error" is "wandering" or "straying". Unlike an illusion, an error or a mistake can sometimes be dispelled through knowledge...
in astronomy.