So my question is regarding how a change in consumer buying behavior affects the CPI. Say for example, that in times of crisis people tend to buy their goods from shops with cheaper prices than the shops that they normally buy from, which would reduce the cost of their purchase.
Would this change be reflected in the calculation of the CPI, leading it to decrease? My first thought was that this change would not be immediately reflected in the calculation of CPI; since the CPI is calculated based on a determined basket of goods, so it would not consider this substitution. But would this change be eventually taken into consideration when adjusting the basket of goods?