This article is meant to be just a common sense analysis about the new Consumer Price Index (CPI) 2007 that has been applied in Bolivia since April 2008.
This subject would not be that important if there weren’t critical changes in the way that this index is calculated (source: Cainco Analysis ). Here are just some concerns that depicts the inflation in this country:
- The CPI 2007 removes some products that had an important incremental price years before.
- The index categories have changed as well as the cities were the samples are taken.
- The new CPI uses a geometric mean while the old one used an arithmetic mean.
There are other considerations that need to be analyzed better like the choice of the basis year 2007 and lack of transparency around this new index. However, I would like to focus on the choice of parameters, the mathematical means, and the potential consequences of this change.
The CPI 2007 products
After browsing for some hours on the INE’s official website, I have not found any information concerning the new CPI 2007 parameters or methodologies. After reading the press, it seems that this information has not been made public in an official way. This lack of transparency makes us wonder if the inflation results based on the CPI 2007 reflects Bolivia’s real inflation (what is the official choice of parameters ?)
Accordingly to the press, there are 60 products removed from the CPI which seemed to have experience an important volatility in the past years. The most important would be: scholar and pre-scholar inscription fees, razor blades, mail stamps, sewing thread, gelatin, shoes cream, oregano, etc.
There are 139 new products and services such as computers, kindergartens, washing machines, microwaves, vehicles, gym services, superior education, natural gas, aerial transportation, vehicle insurance, etc.
The choice of these last products have two issues. First, the prices vary very little in a short term scope since these are products of a long-term duration (e.g. microwaves and washing machines). The same can be applied for services such as kindergartens or superior education where the fees are paid by semester or year. Can these products show the inflation per month of a country when their prices are stable for several months?
The second consideration is that many of these products are imported in dollars. Since the Bolivian peso is currently quite strong in comparison to the dollar, these products depends on the currency value. Because they are not produced in Bolivia and depends on the dollar value, can they be considered as part of a Bolivian index of inflation?
Finally, most of these services/products (e.g. aerial transportation or vehicle insurance) are consumed by a very tiny part of the population. I would be astonished if more than 10% of Bolivians take an airplane once per month. Can these services/products consumed by a small population be part of a National index ?
The CPI 2007 New Categories and new cities
The categories used in the CPI 1991 have changed in CPI 2007 in order to be comparable with the EU and Andean Community (CAN) countries. This can be potentially useful for benchmarking with similar countries.
The samples used to be taken from the 4 most important cities (La Paz, El Alto, Cochabamba y Santa Cruz). The new CPI takes samples from all the major cities in each department (9 in total). The issue here is that together La Paz & El Alto had a 48 % weight and with the new CPI they will only have roughly 29 %. Besides, the population of these cities together reach 2 million people which represents 25% of Bolivian population. The consequence is that an important demographic region will represent less than other cities in the new index.
Another interesting point is that the group Food & Beverages represents 40% of the CPI 2007 index while it was 50% of the CPI 1991. This particular group is considered to be very volatile in the Bolivian economy, having a smaller percentage in the new index implies a smaller incidence of volatility in the overall inflation result. For a country with such a small GDP per capita, food & beverage is more relevant than services or other non-basic products. As a comparison the following table shows the percentage of the Food&Beverage group with the corresponding nominal GDP
- 48% Peru with 4.414 GDP per capita
- 40% Bolivia with 1.665 GDP per capita
- 31 % Chile with 10.125 GDP per capita
- 26% Ecuador with 3.562 GDP per capita
The Geometric vs Arithmetic mean
Mathematically, the Geometric mean cannot be higher than the arithmetic mean. The CPI 1991 was calculated with an arithmetic mean while the CPI 2007 uses the geometric mean. In consequence, the inflation calculated by a geometric mean will be smaller or at most equal than the one calculated by the arithmetic mean.
I cannot say which way is better way to calculate the CPI, but in any case the new index should be benchmarked with the old index for at least 6 months or a year to understand better the difference between both measures and to prepare the transition.
Last Comments
The new changes of the CPI 2007, might underestimate the real value of the inflation since many products chosen as parameters have long-term scope and are not necessarily accessible for most of the Bolivians. At the same time, the Food & Beverage group which is the most important category for the Bolivian economy has been reduced its incidence by 10 %.
If we add the fact that a geometrical mean is used, then it is not surprising at all that the inflation results are smaller with the CPI 2007 than the one that could be obtained with the CPI 1991. This is quite important for all the Bolivians since, as Doria Medina said, the inflation sets the salary increases. If the official inflation is smaller than the real one, all the Bolivians would be paying the gap as an indirect “tax”. For instance, if the real inflation is 10%, but the official one is 8 %, then the salaries are increased by 8 % which means that the 2 % is covered by the population that obviously will get less for their money.
As Bolivian, I can only hope that the economic agenda will be prioritized over the political agenda the next year. Who really cares about a new Constitution if our salary pays less bills than before ?