The nominal interest rate is calculated using the Fisher equation. This economic principle posits that the nominal interest rate equals the sum of the real interest rate and the inflation rate. The formula is:
Nominal Interest Rate = Real Interest Rate + Inflation Rate
Definitions:
In essence, to ascertain the nominal interest rate, add the real interest rate to the inflation rate. The governing formula is:
Nominal Interest Rate = Real Interest Rate + Inflation Rate

In an economy, exclusion of _______ may lead to under estimation of the value of Gross Domestic Product (GDP).