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Industrial Relations: Trends in trade union membership
TRENDS IN TRADE UNION MEMBERSHIP
Changes in industry composition
Trade union membership rates vary considerably across different industries. The highest rates occur in industries such as electricity, gas and water, communication, and public administration and defence which have high public sector employment. Manufacturing, construction and community services all exhibit moderately high rates of trade union membership. Service industries such as wholesale and retail trade, and recreation, personal and other services, and rural industries exhibit relatively low rates of trade union membership.
Much of the growth in the number of employees between 1986 and 1992 was concentrated in the least unionised industries. Recreation and personal services grew by 45%, finance, property and business services by 28%, wholesale and retail trade by 18%, and agriculture, forestry, fishing and hunting by 13%. In contrast, most of the employment loss occurred in highly unionised industries. Electricity, gas and water declined by 23%, and communication by 21%.
Community services was the only industry with a relatively high trade union membership rate to exhibit sufficient job growth over the 1986-92 period to boost its share of total employment. However, over half of this growth was in the private sector which has a relatively low rate of trade union membership. The high rate of trade union membership in the industry as a whole reflects the high rate of membership in the larger public sector component of the industry which also grew, but at a slower rate.
Between 1986 and 1992 the proportion of employees working in industries with higher than average unionisation rates fell from 62% to 58%. Over the same period there was also a shift of 4 percentage points in the proportion of employees in the highly unionised public sector to the private sector, which generally has much lower levels of trade union membership. This was related to the changes in gross industry structure and also incorporated some shifts within industries such as that in community services.
INDUSTRY AND SECTOR OF EMPLOYEES
Growth of permanent part-time and casual work
Trade union membership rates are highest among permanent full-time employees. In 1992, 47% belonged to a trade union compared to 41% of permanent part-time employees and 17% of casual employees.
Some 75% of the job growth between 1986 and 1992 was in part-time work both permanent and casual (see Trends in part- time work). Of the 650,000 jobs created over the period, 319,000 (49%) were casual part-time positions, 167,000 (26%) were permanent part-time positions and 115,000 (18%) were casual full-time positions. Although the number of permanent full-time positions also grew, their share of total employment fell by 7 percentage points.
Increases in permanent part-time work and casual work between 1986 and 1992 occurred in most industries and were not just associated with the pattern of industry change. However, there is a concentration of permanent part-time and casual workers in the high growth industries. In such industries growth in permanent part-time and casual work exceeded growth in permanent full-time work. In industries where employment declined or growth was slow, compositional change was effected through smaller increases in permanent part-time and casual work offset by real declines in permanent full-time work.
EMPLOYMENT STATUS OF EMPLOYEES
Change in the mix of occupations
In 1992 managers and administrators had the lowest rates of trade union membership, followed by salespersons and personal service workers, and clerks. The other 'white collar' occupation groups, professionals and para-professionals, had relatively high rates of trade union membership. At 44%, trade union membership among professionals was as high as among labourers and related workers, the largest 'blue collar' occupation group. Trade union membership among para-professionals (54%) was second highest of all major occupation groups after plant and machine operators, and drivers.
Between 1986 and 1992 employment in professional and para-professional occupations grew by 26% and 14% respectively. However, any positive effect of this growth on aggregate trade union membership rates was most likely offset by even stronger growth in managerial and administrative occupations (29%) and sales and personal service occupations (28%), which have the lowest rates of trade union membership. Added to this there were real declines in the numbers employed in the highly unionised occupation groups of tradespersons, and plant and machine operators, and drivers.
OCCUPATION OF EMPLOYEES
Size of location
Size of employment location has a strong correlation with trade union membership rates, particularly in the private sector. In 1992, 13% of employees in private sector employment locations of less than 10 employees were trade union members. In comparison, locations in the private sector with more than 100 employees had a trade unionisation rate of 51%.
Size of location has only been recorded in the Survey of Trade Union Members since 1990 so an examination of changing patterns of employment concentration over time is not possible from this source. However, some data are available from the Business Register which, although not strictly comparable, provide an indication of the relevant trends.
Between 1986 and 1992 private sector growth was higher in smaller employment locations which have lower than average trade unionisation rates. Although public sector employment increased in absolute terms, it declined in terms of share of total employment with the largest loss of share occurring in large locations.
SECTOR AND LOCATION SIZE OF EMPLOYEES
(b) Union membership rates by size of location were not collected in 1986.
Sources: Survey of Trade Union Members; Business Register
Sex and age structure
Trade union membership rates show marked variation by age and sex. In 1992, 35% of female employees were members of trade unions compared to 43% of male employees. Similarly younger employees had lower rates of trade union membership than older employees, 23% of those aged 15-19 years compared to 46% of those aged 45-59 years. It is not clear whether this pattern is related specifically to age or sex or to the fact that women and younger workers tend to be concentrated in lowly unionised industries and occupations, and in part-time and casual jobs.
The increases in the employment share of women between 1986 and 1992 may have had some negative effect on aggregate trade unionisation levels while the decrease in employment share of younger workers may have had a positive effect.
TRADE UNION MEMBERSHIP RATES, 1992
Source: Survey of Trade Union Members
Total effect of compositional change
One method of quantifying the effects of compositional change on trade union membership is to recalculate aggregate rates while holding compositional elements constant. The resulting standardised estimates can then be compared to the actual rates to gain some idea of the effect that might be attributed to the change in composition3.
Results indicate that, individually, the changes in job status, industry and sectoral composition of the labour force accounted for about a quarter of the decline in trade union membership between 1986 and 1992. Changes in occupation mix and size of employment location each accounted for 10-11% of the decline. The increase in the proportion of female employees had only a small effect on trade union membership accounting for 5% of the decline. Age structure change on its own had the only positive effect on trade union membership rates.
It should be noted that these effects are not additive due to the fact that the various categories are not mutually exclusive and strong correlations exist between the variables. This problem could be eliminated by holding all relevant variables constant simultaneously but the data do not allow sufficient disaggregation for this. However, it seems likely that if all variables were taken into account, well over 30% of the decline in trade union membership could be explained by compositional change4.
FACTOR STANDARDISED(a) TRADE UNION MEMBERSHIP RATE
(a) Standardised to 1986 composition for each factor.
(b) Estimates concerning compositional change in terms of size of location were derived from the Business Register.
Source: Survey of Trade Union Members
1 All data used in this review with the exception of part of Table 5 are derived from the Survey of Trade Union Members and refer to employees in main job.
2 OECD (1991) Employment Outlook.
3 This type of standardisation is generally referred to as shift share analysis.
4 Other earlier research on this issue indicates that around 50% of the decline is due to compositional change, see Peetz, D. (1990) Declining Union Density The Journal of Industrial Relations Vol. 32.