A glance at the 2010 Financial Times MBA rankings underlines the importance of choosing the right school – where you graduate from directly affects your career prospects and earning potential. Yet, in terms of maximising the value of an MBA, when you graduate can be just as important.

The class of 2009 found the going tough, as many companies were looking to shrink or freeze head counts. FT data, collected from business schools as part of the 2010 rankings process, revealed that for those graduates from the most recent academic year actively looking for a job, one in five had not found employment three months after graduation. That represented a doubling of the proportion reported for the same period in 2008.

The figures masked variations between regions. Graduates of North American schools, predominantly looking for work in that region, found it hardest to secure employment within three months of graduation. Some 23 per cent failed to do so. Alumni of Asian schools fared better, with 86 per cent in employment at after three months. Nonetheless, data for all regions showed a worsening of employment prospects for recent MBA graduates in the short term, when compared with 2008.

The impact of the economic downturn on MBA alumni was not limited to the most recent graduates. Alumni of the class of 2006, surveyed by the FT between September and October 2009, reported lower pay compared with their peers from the class of 2005. Overall, salaries three years after graduation were down 1.5 per cent, falling to an average of $121,000 (based on purchasing power parity, or PPP, equivalents).

This drop, though not dramatic, diminished the return on investment of studying for an MBA. The class of 2006 – who earned $61,000 on average before starting their MBA – received a salary rise of 98 per cent three years after graduation, a fall of 7 percentage points on the previous year.

Nonetheless, most alumni surveyed in 2009 were satisfied with their career development following the MBA: 87 per cent of those who responded reported that they achieved both aims of career progression and higher earnings.

An updated analysis of salary data from previous FT MBA surveys, based on the latest available PPP rates for each year, highlights the prolonged effect of past recessions on MBA earnings. In 2002, when the class of 1999 was surveyed, the average salary three years after graduation amounted to $120,800. By 2003, following the impact of the dotcom crash and the terrorist attacks of September 11 2001, salaries reported were almost 4 per cent lower, reflecting, among other things, a tighter job market and a reduction in bonus payments.

The class of 2001 bore the brunt of the recession, though. Joining the job market at the height of the crash, they reported the lowest salaries, earning $113,000 on average. It was not until 2006 that salaries picked up again, with an annual increase of 4.6 per cent, to reach $119,200.

Following growth in 2007 and, to a lesser extent 2008, data for 2009 revealed the average had returned to a similar level as in 2002.

Behind these trends in salary data at the aggregate level, there are some differences between industrial sectors. The finance and banking sector – employer of the biggest proportion of alumni surveyed by the FT – is traditionally the home of the highest salaries for MBA graduates. However, perhaps as a result of the prevailing bonus culture of many organisations in the sector, salaries of those in banking and finance saw the biggest reduction in absolute terms post-2002, falling from an average of $156,000, to a low of $131,500 in 2005. In spite of increases in both 2006 and 2007, salaries remained below the high of 2002, at $133,000 in 2009.

Over the same period, salaries in the consultancy sector, the second most popular for MBA graduates, converged towards the finance and banking average. The public and not-for-profit sector bucked the salary trend, with 2009 levels of remuneration up 11 per cent on those reported in 2002, albeit from a low base ($82,200-$91,000).

As any MBA student knows, past performance is not a guide to the future. However, it is not hard to imagine that MBA salaries over the coming years will follow a similar path to that seen post-2001. The full impact of the latest downturn will not be evident until the class of 2009 reports to the FT in 2012.