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Da standardiserede IQ-test blev først udviklet i det tidlige 20. århundrede, scorede piger typisk højere end drenge indtil 14 årsalderen, hvorefter gennemsnittet for piger faldt under IQ-gennemsnittet for drenge.<ref name=Rider>{{cite book|last=Rider|first=Elizabeth A.|title=Our Voices: Psychology of Women|year=2000|publisher=Wadsworth|location=Belmont, California|isbn=0-534-34681-2|page=202}}</ref> Som testmetoderne blev revideret, blev der gjort en indsats for at udligne kønsforskelle i IQ-testresultater.<ref name=Rider/><ref>Archer, John, Barbara Bloom Lloyd, ''Sex and Gender'', Cambridge University Press, 2002, ISBN 0-521-63533-0, ISBN 978-0-521-63533-2{{page needed|date=June 2013}}</ref><ref>Sternberg, Robert J., ''Handbook of Intelligence'', Cambridge University Press, 2000, ISBN 0-521-59648-3{{page needed|date=June 2013}}</ref>
'''Arbejdsmarkedsøkonomi''' forsøger at forstå funktionen og dynamikken af markedet for arbejde. Arbejdsmarkedet fungerer gennem interaktion mellem arbejdstagere og arbejdsgivere. Arbejdsmarkedsøkonomi ser på udbuddet af arbejdskraft (arbejdere), efterspørgslen efter arbejdskraft (arbejdsgivere) og forsøger på at forstå den resulterende mønster af løn, beskæftigelse og indkomst.
Spredningen af mandlige IQ-scorer er større end for kvinder, hvilket resulterer i flere mænd end kvinder i toppen og bunden en IQ-distrubtion.<ref name="Deary">{{cite journal |doi=10.1016/j.intell.2006.09.003 |title=Brother–sister differences in the ''g'' factor in intelligence: Analysis of full, opposite-sex siblings from the NLSY1979 |year=2007 |last1=Deary |first1=Ian J. |last2=Irwing |first2=Paul |last3=Der |first3=Geoff |last4=Bates |first4=Timothy C. |journal=Intelligence |volume=35 |issue=5 |pages=451–6}}</ref> En undersøgelse konkluderede, at efter kontrol for sociodemografiske og sundhedsmæssige variabler, har [[køn]]sforskelle en tendens til at forsvinde på tests, hvor der var en mandlig fordel.<ref name="jorm">{{cite journal |doi=10.1016/j.intell.2003.08.001 |title=Gender differences in cognitive abilities: The mediating role of health state and health habits |year=2004 |last1=Jorm |first1=Anthony F. |last2=Anstey |first2=Kaarin J. |last3=Christensen |first3=Helen |last4=Rodgers |first4=Bryan |journal=Intelligence |volume=32 |pages=7–23}}</ref> En undersøgelse foretaget af [[james Flynn]] og Lilia Rossi-Case (2011) fandt, at mænd og kvinder opnåede omtrent lige IQ-scorer via IQ-testen Ravens Progressive Matricer i fem vestlige lande.<ref name="flynn">{{cite journal |doi=10.1016/j.paid.2010.12.035 |title=Modern women match men on Raven's Progressive Matrices |year=2011 |last1=Flynn |first1=Jim |authorlink1=Jim Flynn (academic) |last2=Rossi-Casé |first2=Lilia |journal=Personality and Individual Differences |volume=50 |issue=6 |pages=799–803}}</ref>
I økonomi er arbejdskraft et mål for det arbejde gjort af mennesker. Det er traditionelt i kontrast til andre produktionsfaktorer såsom jord og kapital. Der er teorier, der har udviklet et koncept kaldet menneskelig kapital (med henvisning til de færdigheder, at arbejdstagere besidder, ikke nødvendigvis deres egentlige arbejde).
Der er to sider af arbejdskraft økonomi. Labour økonomi kan generelt ses som anvendelse af mikroøkonomiske eller makroøkonomiske teknikker til arbejdsmarkedet. Mikroøkonomiske teknikker studerer rolle enkeltpersoner og enkeltvirksomheder på arbejdsmarkedet. Makroøkonomiske teknikker ser på sammenhængen mellem arbejdsmarkedet, markedet for varer, pengemarkedet, og markedet for udenrigshandel. Det ser på, hvordan disse interaktioner indflydelse makro variabler som beskæftigelsen, erhvervsfrekvens, samlede indkomst og bruttonationalprodukt.
==The macroeconomics of labour markets==
The [[labor force]] is defined as the number of people of [[working age]], who are either employed or actively looking for work. The '''participation rate''' is the number of people in the labour force divided by the size of the adult [[civilian noninstitutional population]] (or by the population of working age that is not [[Institutionalisation|institutionalised]]). The '''nonlabour force''' includes those who are not looking for work, those who are institutionalised such as in prisons or psychiatric wards, stay-at home spouses, children, and those serving in the military. The '''[[unemployment]] level''' is defined as the labour force minus the number of people currently employed. The '''unemployment rate''' is defined as the level of unemployment divided by the labour force. The '''employment rate''' is defined as the number of people currently employed divided by the adult population (or by the population of working age). In these [[statistics]], self-employed people are counted as employed.
Variables like employment level, unemployment level, labour force, and unfilled vacancies are called '''stock variables''' because they measure a quantity at a point in time. They can be contrasted with '''flow variables''' which measure a quantity over a duration of time. Changes in the labour force are due to flow variables such as natural population growth, net immigration, new entrants, and retirements from the labour force. Changes in unemployment depend on: inflows made up of non-employed people starting to look for jobs and of employed people who lose their jobs and look for new ones; and outflows of people who find new employment and of people who stop looking for employment. When looking at the overall macroeconomy, several types of unemployment have been identified, including:
* '''Frictional unemployment''' — This reflects the fact that it takes time for people to find and settle into new jobs. If 12 individuals each take one month before they start a new job, the aggregate unemployment statistics will record this as a single unemployed worker. Technological advancement often reduces frictional unemployment, for example: internet search engines have reduced the cost and time associated with locating employment.
* '''Structural unemployment''' — This reflects a mismatch between the skills and other attributes of the labour force and those demanded by employers. If 4 workers each take six months off to re-train before they start a new job, the aggregate unemployment statistics will record this as two unemployed workers. Rapid industry changes of a technical and/or economic nature will usually increase levels of structural unemployment, for example: widespread implementation of new machinery or software will require future employees to be trained in this area before seeking employment. The process of [[globalisation]] has contributed to structural changes in labour, some domestic industries such as textile manufacturing have expanded to cope with global demand, whilst other industries such as agricultural products have contracted due to greater competition from international producers.
* '''Natural rate of unemployment''' — This is the summation of frictional and structural unemployment, that excludes cyclical contributions of unemployment e.g. recessions. It is the lowest rate of unemployment that a stable economy can expect to achieve, seeing as some frictional and structural unemployment is inevitable. Economists do not agree on the natural rate, with estimates ranging from 1% to 5%, or on its meaning — some associate it with "non-accelerating [[inflation]]". The estimated rate varies from country to country and from time to time.
* '''Demand deficient unemployment''' — In [[Keynesian economics]], any level of unemployment beyond the natural rate is most likely due to insufficient demand in the overall economy. During a recession, [[aggregate expenditure]], is deficient causing the underutilisation of inputs (including labour). Aggregate expenditure (AE) can be increased, according to Keynes, by increasing consumption spending (C), increasing investment spending (I), increasing government spending (G), or increasing the net of exports minus imports (X−M). <br /> {AD = C + I + G + (X−M)}
==Microeconomics of labour markets==
[[neoclassical economics|Neoclassical economists]] view the labour market as similar to other markets in that the forces of [[supply and demand]] jointly determine price (in this case the wage rate) and quantity (in this case the number of people employed). However, the labour market differs from other markets (like the markets for goods or the financial market) in several ways. Perhaps the most important of these differences is the function of supply and demand in setting price and quantity. In markets for goods, if the price is high there is a tendency in the long run for more goods to be produced until the demand is satisfied. With labour, overall supply cannot effectively be manufactured because people have a limited amount of time in the day, and people are not manufactured.
The labour market also acts as a [[market clearing|non-clearing market]]. While according to neoclassical theory most markets have a point of equilibrium without excess surplus or demand, this may not be true of the labour market: it may have a persistent level of unemployment. Contrasting the labour market to other markets also reveals persistent [[compensating differential]]s among similar workers. Models that assume [[perfect competition]] in the labour market, as discussed below, conclude that workers earn their [[marginal product]] of labour.<ref>{{cite web |title=The Micro-Economics of Surplus Labour|url=http://www.econ.yale.edu/growth_pdf/cdp772.pdf|publisher=Yale University|author=Gustav Ranis|date=February 1997}}</ref>
[[Fil:Labour_economics-shortrun_supply_smaller.png|frame]]
Households are suppliers of labour. In microeconomic theory, people are assumed to be rational and seeking to maximize their [[utility function]]. In the labour market model, their utility function expresses trade-offs in preference between leisure time and income from time used for labour. However, they are constrained by the hours available to them.
Let ''w'' denote the hourly wage, ''k'' denote total hours available for labour and leisure, ''L'' denote the chosen number of working hours, π denote income from non-labour sources, and ''A'' denote leisure hours chosen. The individual's problem is to maximise utility ''U'', which depends on total income available for spending on consumption and also depends on time spent in leisure, subject to a time constraint, with respect to the chooses of labour time and leisure time:
:<math>\text{maximize} \quad U(wL + \pi, A) \quad \text{subject to} \quad L + A \le k.</math>
This can be shown in a graph that illustrates the trade-off between allocating time between leisure activities and income-generating activities. The linear constraint indicates that there are only 24 hours in a day, and individuals must choose how much of this time to allocate to [[leisure]] activities and how much to [[wage labour|working]]. This allocation decision is informed by the [[indifference curve]] labelled IC. The curve indicates the combinations of leisure and work that will give the individual a specific level of utility. The point where the highest indifference curve is just tangent to the constraint line (point A), illustrates the optimum for this supplier of labour services.
==Information approaches==
In many real-life situations the assumption of perfect information is unrealistic. The firm does not necessarily know how hard a worker is working or how productive they are. This provides an incentive for workers to [[laziness|shirk]] from providing their full effort — since it is difficult for the employer to identify the hard-working and the shirking employees, there is no incentive to work hard and productivity falls overall, leading to more workers being hired and a lower unemployment rate.
One solution used recently{{when|date=June 2012}} ([[stock options]]) grants employees the chance to benefit directly from the firm's success. However, this solution has attracted criticism as executives with large stock option packages have been suspected of acting to over-inflate share values to the detriment of the long-run welfare of the firm. Another solution, foreshadowed by the rise of [[temporary work]]ers in Japan and the [[Haken-giri|firing of many of these workers]] in response to the financial crisis of 2008, is more flexible job contracts and terms that encourage employees to work less than full-time by partially compensating for the loss of hours, relying on workers to adapt their working time in response to job requirements and economic conditions instead of the employer trying to determine how much work is needed to complete a given task and overestimating.
Another aspect of uncertainty results from the firm's imperfect knowledge about worker ability. If a firm is unsure about a worker's ability, it pays a wage assuming that the worker's ability is the average of similar workers. This wage undercompenstates high ability workers and may drive them away from the labour market. Such phenomenon is called [[adverse selection]] and can sometimes lead to market collapse.{{citation needed|date=June 2012}}
There are many ways to overcome adverse selection in labour market. One important mechanism is called [[Signalling (economics)|signalling]], pioneered by [[Michael Spence]].<ref>{{cite journal |year=1973 |month= |title=Job Market Signaling |journal=[[Quarterly Journal of Economics]] |volume=87 |issue=3 |pages=355–374 |jstor=1882010|doi=10.2307/1882010 |publisher=The MIT Press }}</ref> In his classical paper on job signalling, Spence showed that even if formal education does not increase productivity, high ability workers may still acquire it just to signal their abilities. Employers can then use education as a signal to infer worker ability and pay higher wages to better educated workers. It may appear to an external observer that education has raised the marginal product of labor, without this necessarily being true.
==Referencer==
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[[ast:Mercáu de trabayu]]
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