Changes in the occupational distribution of an economy can be used to identify and analyse stages of development. In the textbook case of economic development, when labour flows from agriculture to the industrial and services sectors, these flows will be visible in the occupational distribution as well. The share of skilled agricultural and fishery workers will decrease, while rising educational attainment levels are likely to be reflected in a decreasing share of elementary occupations and rising shares of high-skilled occupational groups such as professionals and technicians.

In developed economies, which already have relatively well-educated labour forces, increases in the shares of high-skilled occupational groups are associated with the advance of the knowledge economy and additional changes in the structure of economies. Furthermore, shifts within occupational groups may be equally important. For example, the growing importance of information and communication technology (ICT) has resulted in a proliferation of ICT-related jobs. Similarly, aging of populations in many advanced economies has led to an expansion of the number of health professionals and health associate professionals.

The breakdown of the indicator by sex allows for an analysis of gender segregation of employment. Division of labour markets on the basis of sex is one of the most pervasive characteristics of labour markets around the world, which is reflected in differentials in occupational distributions between men and women. Such differentials can be analysed at detailed levels of the occupational classification,1but even at the most aggregated level, large differences by sex are evident.

Despite much progress in recent decades, gender inequalities remain pervasive in many dimensions of life - worldwide. But while disparities exist throughout the world, they are most prevalent in developing countries. Gender inequalities in the allocation of such resources as education, health care, nutrition, and political voice matter because of the strong association with well-being, productivity, and economic growth. These patterns of inequality begin at an early age, with boys routinely receiving a larger share of education and health spending than do girls, for example.

The female share of high-skilled occupations such as legislators, senior officials, and managers indicates gender segregation of employment. Women are vastly underrepresented in decision-making positions , although there is some evidence of recent improvement.
Female legislators, senior officials and managers (% of total)
Most of the information derives from labour force surveys. In a limited number of countries the information is derived from other household surveys, population censuses, and official estimates. There are many differences in how countries define and measure employment status, particularly members of the armed forces, self-employed workers, and unpaid family workers. Where members of the armed forces are included, they are allocated to the service sector, causing that sector to be somewhat overstated relative to the service sector in economies where they are excluded. Where data are obtained from establishment surveys, data cover only employees; thus self-employed and unpaid family workers are excluded. In such cases the employment share of the agricultural sector is severely underreported. Caution should be also used where the data refer only to urban areas, which record little or no agricultural work. Moreover, the age group and area covered could differ by country or change over time within a country. For detailed information, consult the original source.

Countries also take different approaches to the treatment of unemployed people. In most countries unemployed people with previous job experience are classified according to their last job. But in some countries the unemployed and people seeking their first job are not classifiable by economic activity. Because of these differences, the size and distribution of employment by economic activity may not be fully comparable across countries.
Female legislators, senior officials and managers (% of total) refers to the share of legislators, senior officials and managers who are female.
The indicator for employment by occupation classifies jobs into major groups, with the groups defined by the classification that is used. Most internationally comparable data currently available are classified according to the International Standard Classification of Occupations, 1988 (ISCO-88), with the following major groups (1) Legislators, senior officials and managers; (2) Professionals; (3) Technicians and associate professionals; (4) Clerks; (5) Service workers and shop and market sales workers; (6) Skilled agricultural and fishery workers; (7) Craft and related trades workers; (8) Plant and machine operators and assemblers; (9) Elementary occupations; and (10) Armed forces.

A job is defined as a set of tasks and duties performed, or meant to be performed, by one person, including for an employer or in self-employment. An occupation is defined as a set of jobs whose main tasks and duties are characterised by a high degree of similarity.2Occupational classifications categorize all jobs into groups, which are hierarchically structured in a number of levels.

The ten major groups in ISCO-88 and the most recent revision, ISCO-08, are associated with four broad skill levels. These levels are defined in relation to the levels of education specified in the International Standard Classification of Education (ISCED). The use of ISCED categories to assist in defining the four skill levels does not imply that the skills necessary to perform the tasks and duties of a given job can be acquired only through formal education. The skills may be, and often are, acquired through (informal) training and experience. In addition, it should be emphasized that the focus in both ISCO-88 and ISCO-08 is on the skills required to carry out the tasks and duties of an occupation, and not on whether a worker employed in a particular occupation is more or less skilled than another worker in the same occupation.

Employment is defined as persons above a specified age who performed any work at all, in the reference period, for pay or profit (or pay in kind), or were temporarily absent from a job for such reasons as illness, maternity or parental leave, holiday, training or industrial dispute. Unpaid family workers who work for at least one hour should be included in the count of employment, although many countries use a higher hour limit in their definition.
Data on employment are drawn from a variety of sources including labor force surveys, household surveys, official estimates, and censuses. In a very few cases and only where other types of sources are not available, information is derived from insurance records and establishment surveys Employment data include both full-time and part-time workers.