Many experts say that the major problem that Nigeria needs to tackle is corruption. Even the government knows it as they usually include it in their manifestos. Gradually, corruption has been absorbed into our culture as normal. Corruption is flowing from the government to the poor man on the street. A job seeker may have to tip the secretary before he can see the boss or even before his application can be accepted. When someone gets a government’s appointment into an office, members of his family and his friends are already seeing him as a rich man. Corruption is a virus that can collapse a system. It needs to be tackled before it becomes incurable.
Besides the devastating effect in a country, corruption has several global consequences, such as in global economy, human rights, and environmental degradation. Corruption has been linked to be strongly intertwined with one of the biggest challenges humanity currently faces: climate change.
Before we can tackle corruption, we need a measuring device, a barometer sort of, to be able to monitor the progress or decline in improvement. Fortunately, Transparency International, a non-governmental organization, has provided a robust tool to monitor corruption. The organization has been publishing what is called “The Corruption Perceptions Index (CPI)” over several countries and territories annually since 1995. The number of countries were initially 174, and by 2011, it has grown to 180.
The Corruption Perceptions Index (CPI) is an index that scores and ranks countries by their,perceived levels of public sector corruption. It measures how corrupt each country’s public sector is perceived to be, as assessed by experts and business executives. The CPI generally defines corruption as an “abuse of entrusted power for private gain”. This can involve a range of illicit or dishonest activities, such as bribery, fraud, embezzlement, nepotism, and extortion. It occurs when officials misuse their authority for personal benefit, which can lead to distorted policies, misallocated resources, and a breakdown of public trust.
A country’s score is the perceived level of public sector corruption. From 1995 to 2011, the index was scored on a scale of 10 to 0. Since 2012, the CPI ranks on a scale from 100 (very clean) to 0 (highly corrupt). A higher score indicates greater transparency (i.e., less corruption).
A country’s rank is its position relative to the other countries in the index. Ranks can change merely if the number of countries included in the index changes. The rank is therefore not as important as the score in terms of indicating the level of corruption in that country.
The CPI is the most widely used global corruption ranking in the world. It measures how corrupt each country’s public sector is perceived to be, according to experts and business executives. It is one of the tools investors from foreign countries use to determine whether to invest in Nigeria or not. Therefore, it is a tool the federal government needs to consider seriously. The tool can help to check on history of corruption, develop policies, and strategize on how to tackle corruption.
Although widely used as a key indicator of corruption, the CPI does not capture all forms of corruption. The index focuses solely on the public sector. The index is called perceptions index of corruption due to the difficulty of measuring absolute levels of corruption. The CPI methodology enables consistent comparison of corruption perceptions across countries each year. It goes through four stages:
- selecting data sources,
- rescaling them to a uniform 0–100 scale,
- aggregating the results, and
- estimating uncertainty.
Data selection stage captures expert and business leader assessments of various public sector corruption practices. This includes bribery, misuse of public funds, abuse of public office for personal gain, nepotism in civil service, and fraud. Since 2012, CPI has taken into account surveys and assessments from these 12 different institutions:
- African Development Bank (based in Ivory Coast)
- Bertelsmann Foundation (based in Germany)
- Economist Intelligence Unit (based in the UK)
- Freedom House (based in the US)
- Global Insight (based in the US)
- International Institute for Management Development (based in Switzerland)
- Political and Economic Risk Consultancy (based in Hong Kong)
- The PRS Group, Inc. (based in the US)
- World Bank
- World Economic Forum
- World Justice Project (based in the US)
- Varieties of Democracy Project
Countries need to be evaluated by at least three of these sources to appear in the CPI.
Global Overview
Corruption is an evolving global threat that does far more than undermine development – it is a key cause of declining democracy, instability and human rights violations. The international community and every nation must make tackling corruption a top and long-term priority. This is crucial to pushing back against authoritarianism and securing a peaceful, free and sustainable world. The dangerous trends revealed in this year’s Corruption Perceptions Index highlight the need to follow through with concrete action now to address global corruption.
Looking at the CPI data, it is correct to conclude that every country in the world is corrupt to a certain degree. Since 2012, there has been a consistent trend. Denmark, Finland, and New Zealand have been mostly in the top 3 cleanest countries in the world. Denmark, with an average score of 90, conceded the top position only in 2017 to New Zealand. Somalia, with an average score of 9, occupies the bottom position most of the years, sharing it occasionally with South Sudan or North Korea.
Of the 180 countries ranked in the 2024 CPI, published in February 2025, Nigeria was ranked 140th with a score of 26. The top scorers included Denmark (90), Finland (88), Singapore (84), while those perceived as the most corrupt included South Sudan (8), Somalia (9) and Venezuela (10). So, South Sudan, ranked 180th, was perceived as the most corrupt country in 2024. The US, with a score of 65, ranked 28th out of 180 countries; this ranking reflects a decline in its previous score of 69 and a new low since the index began.
The 2024 CPI shows that corruption is a dangerous problem in many parts of the world. Since 2012, only 32 countries have significantly reduced their corruption levels. 148 countries (including Nigeria) have stayed stagnant or gotten worse during the same period.
Nigeria
From 2012 to 2024, we are able to capture the CPI for 3 governmental regimes: Jonathan (partially), Buhari (fully), and Tinubu (partially). Shown in the graphs below, are the trends in score and in ranking. The rank is given for both from top and from bottom because the number of countries surveyed are not uniform across those years.
The scores for the last four years of President Jonathan administration fluctuate every year. This interprets to mean that there was no specific policy in place to tackle corruption. The highest score Nigeria ever had is 28 in 2016 (ranked 136th) and the lowest is 24 in 2021 (ranked 154th), both during the tenure of Buhari. This makes his regime the better one to study for the Tinubu administration. The question we need to ask is: what was President Buhari doing right against corruption at the beginning of his tenure that slipped away towards the end of his tenure? President Tinubu has started well with only one data point. We cannot really assess if he has a policy in place to tackle corruption until March 2027, when we will have two more data points.
As mentioned earlier, rank is not as important as the score in terms of indicating the level of corruption, in that, ranks can change if the number of countries included in the index changes. For example, 2014 to 2016 indicate the best rank (136th) when counting from the top. However, only 168 countries were surveyed in 2015, which makes Nigeria’s rank to be close to the bottom (32nd from bottom). All the same, we can deduce that Nigeria’s worst rank is in 2021, which was closest to the bottom (26th from bottom) and farthest from the top (154th from top). The CPI rank trend is encouraging from that year 2021 till now. Again, President Tinubu is doing well in improving the CPI rank both from top (140th) and from bottom (40th).
- Professor Abi Olowe teaches Petroleum Engineering in Houston, Texas
