In its latest survey on corruption, the Washington-based World Bank says corruption in 26 former socialist countries and Turkey has eased in recent years.
The report finds that countries implementing the strongest market-based economic reforms have registered the most progress against corruption.
World Bank economists say Slovakia and Estonia are major success stories. They are among the transition countries that have moved to flat-rate taxation that both simplifies tax collection and reduces tax evasion.
Overall, progress has been greatest in tax and customs administration. Bribe paying has also improved since an earlier report in 2002.
Report co-author James Anderson says follow-through and leadership are critical to success.
"What we actually find is that the countries that had the most success are the ones that followed through on these changes in laws and policies and really had strong leadership in putting them through to implementation," he said.
But the survey of more than 7,000 enterprises finds that corruption in post-communist countries is significantly higher than in Western Europe. In Albania, for example, two-thirds of all companies said corruption is a major problem.
The Kyrgyz Republic and Albania are among the countries where corruption is said to be getting worse.
"Albania is also generally along most indicators the second worst [after Kyrgyz Republic] and sometimes the worst, and is also not getting better," said Cheryl Gray, co-author of the report. "Now, both of these countries have had changes of government since the survey and the new governments have been very committed to addressing this problem."
Russia, Serbia, and Macedonia have also registered little progress with companies there reporting that bribes are often necessary to get things done.
The report finds that the promise of EU membership has been a powerful incentive to fight corruption. Romania and Bulgaria, both hoping to join the European Union in 2007, have registered significant progress.
Key components of success are a free media, transparency in government procurement, judicial reform, and strong enforcement of anti-corruption laws.