The Minimum Wage

1. The Minimum Wage

2. Systems of Minimum Wages • System of minimum wages vary across countries – 2 most common systems are: • statutory minimum wage (set by govt or in national collective bargain) • set by sectoral collective bargains with extension to non-signatory employers • Some countries have a single minimum (e.g. US), others have variation by age, region, industry, occupation • Measure of bite of minimum wage: • Kaitz index = minimum/median • Spike – percentage of workers at minimum

3. Kaitz Index – selected countries

4. Kaitz Index – Selected Countries

5. Summary • Minimum wage lowest in US, highest in France – but age variation in FR, not US • For teenagers US Kaitz 80-90% • Most countries have Kaitz index of 40-50% • No big increases in recent years – most countries have falls

6. Introduction • Have introduced in context of institutions that might affect wage inequality • But will also have discussion about impact on employment as this is often regarded as most interesting question

7. Minimum Wage and Employment • Competitive model has a very clear prediction • Minimum wage above market-clearing wage will cause job losses • Follows from the fact that factor demand curves slope downwards • As w=MRPL any increase in wage makes marginal worker unprofitable

8. supply wage Minimum wage MRPL employment A Picture

9. Any models with a different prediction? • Monopsony models can have a different prediction. • Starting from wage chosen by monopsonist an increase in their wage will raise employment • Intuition: • MRPL=MCL>w so marginal worker still profitable after rise in wage and more workers want to work • Employment is supply-determined and increased wage increases labour supply • Minimum wage raises average cost of labour but reduces marginal cost: MCL=w(N)+w’(N)N

10. MCL supply wage Minimum wage MRPL employment A Picture

11. Can one raise the minimum wage and employment without limit? • Does not sound very plausible • Will not be possible – there comes a point where employment demand determined – can think of N=min(Ns(w),Nd(w)) • Employment will be maximized at wage where Ns(w)=Nd(w) i.e. market-clearing wage • This is efficient minimum wage to set

12. How useful is this in practice? • Market-clearing wage different in different labour markets – by age, education, region • Typically minimum wage does not have much variation – too high in some markets, too low in others. • It is a blunt policy instrument • Also have only considered single employer – interactions are likely to be important

13. Models of Oligopsony • May have very different prediction about employment effect of minimum wage • E.g. suppose labour supply curve is: Ni=Bi(Wi/W)ε • Where W is average wage • Then each employer has some monopsony power but raising minimum wage does not raise employment

14. Conclusion on Theory • Competitive model has clear prediction • Monopsony prediction ambiguous • Therefore should look at evidence with open mind • Until Card-Krueger ‘Myth and Measurement’ consensus in US was small negative employment effect especially for teenagers – they challenged this

15. Card-KruegerMyth and Measurement • Re-examined all evidence for negative employment effects of minimum wage • Look at variety of natural experiments • Concluded no evidence for view that minimum wage causes job loss • Will focus on NJ/PA study as that is most famous • also Card-Krueger, AER 94 • Neumark-Wascher, + Card-Krueger, AER 00

16. The NJ/PA Study • US system of minimum wages is a federal minimum with individual states choosing higher minimum if they want • in 1992 NJ raised its minimum wage to $5.05 above the federal minimum of $4.25 • NJ fast food restaurants the treatment group, restaurants in eastern PA the control group • Data collected by phone interview before and after rise in NJ minimum wage

17. A Map

18. Effect on Wages

19. Basic Results – Difference in Difference Estimator

20. Neumark-Wascher Criticism • They argued data was of very poor quality, especially on dependent variable – does this matter? • Got hold of payroll data and claimed to find evidence of negative employment effects • Unfortunately some of this data was supplied by noted opponent of minimum wage so perhaps not random sample • Results strongest in this sub-sample • Perhaps some evidence of reduction in hours per worker • See AER 2000 for exchange and make your own mind up

21. Longer Time Series Using Administrative Data

22. Evidence on Employment Effects for other Countries • The UK: • Studies of introduction of NMW in 1999 • Aggregate studies failed to find any impact • Machin, Manning, Rahman did find small negative effect among care workers where 30% affected • Problem for many other countries is lack of big change to be basis of natural experiment • E.g. France – SMIC seems very high but lack of much variation in recent years means that hard to evaluate

23. Machin, Manning, RahmanJEEA, 2003 – Research Design • Sample of care workers in retirement homes for elderly – very low paid job • Surveyed both before and after introduction of NMW • Some homes unaffected as initially paid above NMW – these are effectively the control group • Look at change in hours and employment

24. Machin, Manning, RahmanJEEA, 2003 - Results

25. The Minimum Wage and Wage Inequality • Yet again, most research for US • Consensus was that minimum wage unimportant for wage inequality as <5% of workers paid the minimum wage • This was challenged by: • Dinardo, Fortin, Lemiuex, Ecta, 1996 • Lee, QJE 1999

26. diNardo, Fortin, Lemiuex • Pointed out that minimum wage had a very obvious effect on wage distribution in 1979 • Because it did not change in nominal terms in period until 1990, declined in real terms so seemed unimportant by the end • But can help to explain rise in lower-end wage inequality • Especially true for women

27. A Picture to give flavour of results

28. Lee, QJE 1999Basic idea • Federal minimum wage does not vary across states but average level of wages does so minimum wage more important in AK than in NY • If minimum wage important for wage inequality should see bigger rise in wage inequality in low-wage states • This is what he finds

29. A Picture to Summarize Results

30. Interpretation • Low-end wage inequality initially much smaller in low-wage states in 1979 – consistent with minimum wage being important • Low-end wage inequality then rises much faster in low-wage states • Top-end wage inequality similar in low- and high-wage states and shows no trend • Concludes that min wage can explain almost all of rise in low-end wage inequality in 1980s • Implies substantial spill-overs

31. Evidence from 1990s – Manning, 2003

32. But still a lot of scepticism – Autor, Katz, Kearney

33. Autor-Katz-KearneyExhibit B

34. Evidence from UK • Initial studies of impact effect of introduction of NMW suggested modest effect because only 5% directly affected and there seemed no spilll-overs e.g. Dickens-Manning, EJ 2004 • But perhaps some indication that more powerful in longer-run • Perhaps can explain most or all or reduction in low-end wage inequality in UK – but can’t explain the top

35. The Care Workers Data