An £18,000 net average pay gap between university faculty in Europe and the US has been highlighted in a global analysis of academic careers.
The study, by the Academic Careers Observatory (ACO), part of the European University Institute's Max Weber Programme, found that faculty at European universities earned an average salary, after tax, of £31,575, compared with £49,411 in the US.
It also found wide variations in pay within Europe. The average annual salary in the UK is £41,529, which is significantly higher than the European average but still far short of the sums on offer in the US.
Only Austria, with average net salaries of £47,630, the Netherlands (£44,633), Switzerland (£46,585) and Luxembourg (£44,2) can compete with the US on pay after both salary and the cost of living are taken into account, the ACO analysis says.
The report also highlights how the various pay systems affect staff performance by comparing Italy and the US.
In Italy, it says, pay is linked primarily to length of service. As a result, in 80 per cent of cases salaries at professorial level are higher than in the US. However, "the incentives to perform better in Italy are little, whereas in the US researchers know that an increase in quality publication will lead to a better salary".
The ACO has also attempted to analyse the performance of higher education sectors in different European countries by identifying four different models.
Anglo-Saxon
The Anglo-Saxon model, typified by the UK but also covering Ireland and the Netherlands, is the most "competitive and open" of the four.
This system is also the most successful. The UK's higher education system is the top rated in Europe and is home to the four of the highest-rated European universities.
Under this model, foreign scholars at all levels, from doctorate to visiting professor, are key to encouraging a dynamic culture within universities, and their presence contributes to internationally recognised scientific output, the study says.
Top-level academics are drawn to the Anglo-Saxon model by the high rate of salary increases over a career, which provides a good working incentive, rather than by the starting salaries.
Scholars also value the system for its academic flexibility, freedom from teaching tasks and the quality of administration, all of which contribute to the high quality and quantity of research output, which in turn raises the international standing of its universities.
The study says: "The success of the Anglo-Saxon system depends on a mix of factors, including a healthy competition between universities, decent career prospects in exchange for hard work, high levels of mobility and openness to non-nationals, all of which creates a more vibrant academic community."
Continental
The continental model is used widely across Europe and is dominant in Italy, Germany, Spain and France, the ACO says.
It is less successful in producing world-class universities - the highest ranked institution in Italy, for example, is rated a lowly 136th in the world and 49th in Europe.
This is a more "inner-oriented" model than the Anglo-Saxon one. Recruitment is carried out through informal agreements and there are no guarantees that the best candidate will get a job, the report says.
Promotion tends to be based on seniority and length of service rather than merit, and funding is not linked to academic productivity, which reduces the work incentive.
The study notes that efforts to improve the faults in the system have been made in recent years, but it also points out that the European continental model offers few rewards for young academics, which poses a long-term problem for the international standing of universities.
Scandinavian
The Scandinavian model, which operates in countries such as Sweden, Norway and Denmark, features characteristics of the other two systems.
The report says universities often recruit people they already know and rely heavily on temporary appointments. In this model, it is common for researchers to go back and forth between public and private institutions.
Central-Eastern European
The fourth model is the transnational Central-Eastern European system, which characterises countries "moving out of Soviet-type academic structures to embrace principles of flexibility and market liberalisation".
These countries have booming private-sector provision of higher education and have implemented a range of policies to stop the brain drain to Western Europe, including collaboration with leading universities in other countries.