Did border closure cause food inflation in Nigeria?

BACKGROUND

In August 2019, the Nigerian government partially closed the country's land borders and, in October 2019, halted all trade via land borders. This policy, which remained in effect until December 2020, was aimed at stopping the smuggling of food items into Nigeria.

Government protagonists bragged about the policy. Critiques decried it. One argument commonly peddled in public opposition to the policy is that the border closure led to food scarcity and rapid increases in food prices. But, is this true? Did the policy really cause food inflation in Nigeria? Let's dive into the data and find out!

In the interactive visual below, I present the trajectory of the Consumer Price Index (CPI) for food and non-alcoholic beverages in the period preceding, during and after the border closure (Causal inference diehards might call this an Event Study).  Use the slider at the base of the visual to adjust the view and watch how food prices evolved as the borders closed and opened. Note that the visual is not optimized for  mobile phone screens.