$BTC CPI may overestimate actual inflation due to issues such as failing to fully reflect the substitution effect of consumption (e.g., consumers turning to lower-priced goods) and delays in incorporating new products. Additionally, the method of calculating housing costs (based on imputed rent rather than housing prices) has also sparked controversy. To address these shortcomings, some institutions use the Personal Consumption Expenditures Price Index (PCE) as a supplementary indicator.