According to [1]: "International money laundering and international illicit financial flows (IFFs) are major problems for poor and rich countries alike, but especially the poor. Both are strongly rooted in the fraudulent treatment of imports and exports as they cross international borders. This includes smuggling, misclassification of products to change their valuation, and straight mis-invoicing, i.e. deliberately declaring erroneous product values to make it possible to shift money from one country to another secretly and illegally.

Estimate that 87% of the IFFs in developing countries over the period 2005-2014 resulted from trade mis-invoicing. Detecting undervaluation and misclassification is critical to the fight against tax evasion and IFFs. It is possible to detect these illicit activities by comparing figures on trade flows between pairs of countries. In a perfect world, the details and values of all recorded exports from Albania to Zambia should match the details and values of all recorded imports into Zambia from Albania. These are what are termed mirror statistics. In a perfect world, the reflections would match perfectly. In reality, they never do. Investigating how and why they fail to match is in principle a very good way of helping customs administrations to find out what is going on, and to improve their risk analysis and fraud detection."

[1] https://www.ictd.ac/blog/mirror-statistics-combat-customs-fraud-developing-countries/