A bunch of international groups/institutions try to measure global corruption. Beside the Corruption Perceptions Index (CPI), there are others such as the World Justice Project (WJP) Rule of Law Index, the OECD Public Integrity Indicators (OECD PIIs), the Global Corruption Barometer (GCB), and the Financial Secrecy Index (FSI).
When come to measuring domestic public-sector corruption (bribery, judicial integrity, administrative red tape), e.g corruption within the country, Singapore & Hongkong Ranks as one of the cleanest nations on Earth if you use CPI & WJP. Indonesia is one of the most corrupt countries based on this measure. I believe those who have been living in Indonesia long enough, will agree with this.
However when come to Financial Secrecy & Offshore Abuse (FSI) Singapore & Hong Kong rank among the worst. Indonesia is much cleaner/better. Many people who have seen how the corruption in Indonesia happen could see it why. Unlike Singapore, Hong Kong, the Indonesian conglomerates do not operate a massive global offshore, international financial business hub network. They rely on preferential treatment, protection, plundering the country asset, natural resources which could only work effectively within the countries. Also the collusion between the legislative, executive and judicial power which is hardly found in other countries, is not uncommon in Indonesia.
When come to the household name and the benchmark of macro level corruption the CPI is widely accepted and quoted. But just like big metrics in economics, development or poverty, it also gets its fair share of legitimate criticisms.
Here’s the thing: since corruption happens under the table, it's super hard to measure let alone to quantify it with hard numbers. That’s why broad tools like the CPI end up leaning heavily on expert vibes and perceptions. Since it launched back in 1995 as the first major public index to actually rank countries on corruption, it had a massive head start, which is a big reason it's still the most famous one today.
