Inflation is a measure of how well an economy is performing, with low and stable inflation indicating a well-performing economy. Inflation is defined as a persistent rise in the general price level. While creeping inflation of around 2% can benefit an economy, hyperinflation is bad and can cause political instability. In the UK, inflation is measured using the Consumer Price Index (CPI), which tracks the price of a basket of goods and services and is revised every four years to account for changing consumer trends.