The Demopædia Encyclopedia on Population is under heavy modernization and maintenance. Outputs could look bizarre, sorry for the temporary inconvenience
Multilingual Demographic Dictionary, second unified edition, English volume
Difference between revisions of "15"
(Eugene Grebenik et al., first edition 1958) |
(Etienne van de Walle et al., second 1982 edition *** existing text overwritten ***) |
||
Line 2: | Line 2: | ||
<!--'''15'''--> | <!--'''15'''--> | ||
{{CurrentStatus}} | {{CurrentStatus}} | ||
− | {{Unmodified edition | + | {{Unmodified edition II}} |
{{Summary}} | {{Summary}} | ||
__NOTOC__ | __NOTOC__ | ||
Line 9: | Line 9: | ||
=== 150 === | === 150 === | ||
− | When the movement of a demographic variable in time is considered, a demographic {{TextTerm|time series|1}} is obtained. It is sometimes possible to decompose a time series into a {{TextTerm|trend|2}} around which there are {{TextTerm|fluctuations|3}}, {{TextTerm|variations|3}} | + | When the movement of a demographic variable in time is considered, a demographic {{TextTerm|time series|1}} is obtained. It is sometimes possible to decompose a time series into a {{TextTerm|trend|2}} around which there are {{TextTerm|fluctuations|3}}, {{TextTerm|variations|3}}, or {{TextTerm|deviations|3}} ({{RefNumber|14|1|2}}). Where such fluctuations tend to recur after certain periods, usually several years, they are called {{TextTerm|cyclical fluctuations|4}} or, more generally, {{TextTerm|period fluctuations|4}}. In demography the most common period for compiling data is a year, and the fluctuations in sub-periods of a year are called {{TextTerm|seasonal fluctuations|5}}. The fluctuations that remain after trend, cyclical, and seasonal fluctuations have been eliminated are called {{TextTerm|irregular fluctua-ations|6}}. They may be due to exceptional factors such as wartime mobilization, or sometimes they are {{TextTerm|chance fluctuations|7}} or {{TextTerm|random fluctuations|7}}. 3, In a general sense the term {{NoteTerm|variation}} may be used to describe change in any <br />value or set of values for a variable. |
+ | {{Note|4| {{NoteTerm|Periodic}}, adj. - {{NoteTerm|period}}, n. - {{NoteTerm|periodicity}}, n. {{NoteTerm|cyclical}}, adj. - {{NoteTerm|cycle}}, n.}} | ||
+ | {{Note|7| {{NoteTerm|Random}}, adj.: under the influence of chance (cf. {{RefNumber|16|1|1}}).}} | ||
=== 151 === | === 151 === | ||
− | It is occasionally desirable to replace a series of figures by another that shows greater regularity. This process is known as {{TextTerm|graduation|1}} or {{TextTerm|smoothing|1}}, and it generally consists of passing a | + | It is occasionally desirable to replace a series of figures by another series that shows greater regularity. This process is known as {{TextTerm|graduation|1}} or {{TextTerm|smoothing|1}}, and it generally consists of passing a smooth curve through a number of points in the time series or other series, such as the number of persons distributed by reported age. If a free-hand curve is drawn the process is called {{TextTerm|graphic graduation|2}}. When analytical mathematical methods are used, this is called {{TextTerm|curve fitting|3}}. A mathematical curve is fitted to the data, possibly by the {{TextTerm|method of least squares|4}}, which minimizes the sum of the squares of the differences between the original and the graduated series. Other methods include {{TextTerm|moving averages|5}} or involve the use of the {{TextTerm|calculus of finite differences|6}}. Some of these procedures may be used for {{TextTerm|interpolation|7}}, the estimation of values of the series at points intermediate between given values, or for {{TextTerm|extrapolation|8}}, the estimation of values outside of the range for which it was given. |
− | {{Note|1| {{NoteTerm| | + | {{Note|1| {{NoteTerm|Graduation}}, n. - {{NoteTerm|graduate}}, v. - {{NoteTerm|graduated}}, adj. {{NoteTerm|Smoothing}}, n. - {{NoteTerm|smooth}}, v. - {{NoteTerm|smoothed}}, adj.}} |
− | {{Note|7| {{NoteTerm| | + | {{Note|7| {{NoteTerm|Interpolation}}, n. - {{NoteTerm|interpolate}}, v. - {{NoteTerm|interpolated}}, adj.}} |
− | {{Note|8| {{NoteTerm| | + | {{Note|8| {{NoteTerm|Extrapolation}}, n. - {{NoteTerm|extrapolate}}, v. - {{NoteTerm|extrapolated}}, adj.}} |
=== 152 === | === 152 === | ||
− | It is often necessary to graduate distributions to correct the tendency of people to give their replies in {{TextTerm|round numbers|1}}. | + | It is often necessary to graduate distributions to correct the tendency of people to give their replies in {{TextTerm|round numbers|1}}. {{TextTerm|Heaping|2}} or {{TextTerm|digit preference|2}} is particularly frequent in age distributions and reflects a tendency for people to state their ages in numbers ending with 0, 5, or other preferred digits. {{TextTerm|Age heaping|3}} is sometimes measured with {{TextTerm|indices of age preference|4}}. Age data must often be corrected for other forms of {{TextTerm|age misreporting|5}} or {{TextTerm|age reporting bias|5}}. |
=== 153 === | === 153 === | ||
− | The numerical values of demographic functions are generally listed {{TextTerm| | + | The numerical values of demographic functions are generally listed in {{TextTerm|tables|1}}, such as ''life tables'' ({{RefNumber|43|1|1}}), ''fertility tables'' ({{RefNumber|63|4|1}}), or ''nuptiality tables'' ({{RefNumber|52|2|1}}). A distinction is usually made between {{TextTerm|calendar-year tables|2}} or {{TextTerm|period tables|2}} which are based upon observations collected during a limited period of time, and {{TextTerm|cohort tables|3}} or {{TextTerm|generation tables|3}} which deal with the experience of a cohort throughout its lifetime. A {{TextTerm|multiple decrement table|4}} illustrates the simultaneous effects of several non-renewable events, such as the effects of first marriage and death on the single population. The most used are {{TextTerm|double decrement tables|4}}. |
=== 154 === | === 154 === | ||
− | Where insufficient data exist to | + | Where insufficient data exist to establish the value of a given variable accurately, attempts may be made to {{TextTerm|estimate|1}} this value. The process is called {{TextTerm|estimation|2}} and the resulting value an {{TextTerm|estimate|3}}. Where data are practically non-existent a {{TextTerm|conjecture|4}} may sometimes be made to establish the variable’s {{TextTerm|order of magnitude|5}} . |
=== 155 === | === 155 === | ||
− | Methods of {{TextTerm|graphic representation|1}} or {{TextTerm|diagrammatic representation|1}} | + | Methods of {{TextTerm|graphic representation|1}} or {{TextTerm|diagrammatic representation|1}} may be used to illustrate an argument. The data are represented in a {{TextTerm|figure|2}}, {{TextTerm|graph|2}}, {{TextTerm|statistical chart|2}} or {{TextTerm|map|3}}. A schematic representation of the relationships between variables is often called a {{TextTerm|diagram|4}}, for example the ''Lexis Diagram'' (cf. {{RefNumber|43|7|}}). A graph in which one co-ordinate axis is graduated logarithmically and the other arithmetically is called a {{TextTerm|semi-logarithmic graph|5}}, though such graphs are often inaccurately referred to as {{TextTerm|logarithmic graphs|5}}. A true {{TextTerm|logarithmic graph|6}} has both axes graduated logarithmically and is sometimes referred to as a {{TextTerm|double logarithmic graph|6}}. A frequency distribution may be represented graphically by {{TextTerm|frequency polygons|7}} obtained by joining points representing class frequencies with straight lines, by a {{TextTerm|histogram|8}}, where class frequencies are represented by the area of a rectangle with the class interval as its base, by {{TextTerm|bar charts|9}}, in which the class frequencies are proportionate to the length of a bar or by an {{TextTerm|ogive|10}} representing the cumulative frequency distribution. |
− | |||
− | |||
{{SummaryShort}} | {{SummaryShort}} | ||
{{OtherLanguages|15}} | {{OtherLanguages|15}} |
Revision as of 16:16, 13 November 2006
Disclaimer : The sponsors of Demopaedia do not necessarily agree with all the definitions contained in this version of the Dictionary. The harmonization of all the second editions of the Multilingual Demographic Dictionary is an ongoing process. Please consult the discussion area of this page for further comments. |
Go to: Introduction to Demopædia | Instructions on use | Downloads |
150
When the movement of a demographic variable in time is considered, a demographic time series 1 is obtained. It is sometimes possible to decompose a time series into a trend 2 around which there are fluctuations 3, variations 3, or deviations 3 (141-2). Where such fluctuations tend to recur after certain periods, usually several years, they are called cyclical fluctuations 4 or, more generally, period fluctuations 4. In demography the most common period for compiling data is a year, and the fluctuations in sub-periods of a year are called seasonal fluctuations 5. The fluctuations that remain after trend, cyclical, and seasonal fluctuations have been eliminated are called irregular fluctua-ations 6. They may be due to exceptional factors such as wartime mobilization, or sometimes they are chance fluctuations 7 or random fluctuations 7. 3, In a general sense the term variation may be used to describe change in any
value or set of values for a variable.
- 4. Periodic, adj. - period, n. - periodicity, n. cyclical, adj. - cycle, n.
- 7. Random, adj.: under the influence of chance (cf. 161-1).
151
It is occasionally desirable to replace a series of figures by another series that shows greater regularity. This process is known as graduation 1 or smoothing 1, and it generally consists of passing a smooth curve through a number of points in the time series or other series, such as the number of persons distributed by reported age. If a free-hand curve is drawn the process is called graphic graduation 2. When analytical mathematical methods are used, this is called curve fitting 3. A mathematical curve is fitted to the data, possibly by the method of least squares 4, which minimizes the sum of the squares of the differences between the original and the graduated series. Other methods include moving averages 5 or involve the use of the calculus of finite differences 6. Some of these procedures may be used for interpolation 7, the estimation of values of the series at points intermediate between given values, or for extrapolation 8, the estimation of values outside of the range for which it was given.
- 1. Graduation, n. - graduate, v. - graduated, adj. Smoothing, n. - smooth, v. - smoothed, adj.
- 7. Interpolation, n. - interpolate, v. - interpolated, adj.
- 8. Extrapolation, n. - extrapolate, v. - extrapolated, adj.
152
It is often necessary to graduate distributions to correct the tendency of people to give their replies in round numbers 1. Heaping 2 or digit preference 2 is particularly frequent in age distributions and reflects a tendency for people to state their ages in numbers ending with 0, 5, or other preferred digits. Age heaping 3 is sometimes measured with indices of age preference 4. Age data must often be corrected for other forms of age misreporting 5 or age reporting bias 5.
153
The numerical values of demographic functions are generally listed in tables 1, such as life tables (431-1), fertility tables (634-1), or nuptiality tables (522-1). A distinction is usually made between calendar-year tables 2 or period tables 2 which are based upon observations collected during a limited period of time, and cohort tables 3 or generation tables 3 which deal with the experience of a cohort throughout its lifetime. A multiple decrement table 4 illustrates the simultaneous effects of several non-renewable events, such as the effects of first marriage and death on the single population. The most used are double decrement tables 4.
154
Where insufficient data exist to establish the value of a given variable accurately, attempts may be made to estimate 1 this value. The process is called estimation 2 and the resulting value an estimate 3. Where data are practically non-existent a conjecture 4 may sometimes be made to establish the variable’s order of magnitude 5 .
155
Methods of graphic representation 1 or diagrammatic representation 1 may be used to illustrate an argument. The data are represented in a figure 2, graph 2, statistical chart 2 or map 3. A schematic representation of the relationships between variables is often called a diagram 4, for example the Lexis Diagram (cf. 437-). A graph in which one co-ordinate axis is graduated logarithmically and the other arithmetically is called a semi-logarithmic graph 5, though such graphs are often inaccurately referred to as logarithmic graphs 5. A true logarithmic graph 6 has both axes graduated logarithmically and is sometimes referred to as a double logarithmic graph 6. A frequency distribution may be represented graphically by frequency polygons 7 obtained by joining points representing class frequencies with straight lines, by a histogram 8, where class frequencies are represented by the area of a rectangle with the class interval as its base, by bar charts 9, in which the class frequencies are proportionate to the length of a bar or by an ogive 10 representing the cumulative frequency distribution.
Go to: Introduction to Demopædia | Instructions on use | Downloads |