The inflation rate will show a sharp decline this year when the government adopts a new system of calculating the rise and fall of prices in the economy.

However, experts have are suspicious of the motive behind the new approach. A manager with Uwazi at Twaweza, a Dar es Salaam-based research organisation, Mr Hans Hoogeveen, said when inflation figures based on the new approach are released, they would be irrelevant to the majority of Tanzanians.

But the analyst, who was quick to add that the revision is timely, noting that the figures would only be relevant with regard to urban wage earners.

"This is because the weights given to the various items in the Consumer Price Index (CPI) basket are those derived from the value of consumption of purchased items in urban areas," he told The Citizen last week.

The CPI, he explained, does not take into account the price of goods and services in rural areas, it only incorporates data collected in Dar es Salaam and the regional headquarters.

He added: "On top of that, CPI ignores all the consumption of goods produced by the household such as food from the family land."

The new approach comprises mainly a revision of the weight of food in the CPI, which is the measure of estimating the average price of consumer goods and services purchased by households.

Under the new calculation, the weight of food has been brought down to 44.3 percent of the CPI basket from its current 55.9 per cent contribution. Reliable sources said that adoption of the new formula, which was used to calculate December rates that were released last week, had stalled because some stakeholders, particularly donors, have had reservations over some of its methodological aspects.

A senior official with the Confederation of Tanzania Industries (CTI), Mr Hussein Kamote, said it would be wrong to revise the CPI for political reasons.

"The exercise should be supported by evidence showing that the down weighting of the food item reflects reality on the ground," he said. Noting that he was pessimistic of the motive behind the revision, Prof Humphrey Moshi of the University of Dar es Salaam's Economic Research Bureau (ERB) told The Citizen the new inflation series should portray the real cost of living and doing business in the country.

According to other critics, a new CPI should be tested for 12 months before it is released, which they say is not what NBS did. The Citizen has reliably learnt that NBS tested it for one month and did not share the results with some relevant agencies like the World Bank and the International Monetary Fund (IMF).

"It is due to this shortcoming that the new inflation series will not be released before April as earlier planned," one expert close to the preparations of the new CPI, who preferred anonymity, told The Citizen recently.

NBS's director of census and social statistics, Mr Ephraim Kwesigabo, told The Citizen that the new CPI has not been applied because the IMF and World Bank wants to look at it first.

Mr Thomas Danielewitz of the World Bank's Country Office in Tanzania said recently that the decision on whether or not to start using the new rates in April remains NBS's.

Responding to NBS's claim that the delay to rebase the CPI was caused by some key stakeholders' demand to see it first, Mr Danielewitz asserted that subjecting statistics to thorough analysis by development partners was a normal thing. Experts have said that there are various reasons the IMF and World Bank are interested in the new CPI.

For the IMF, they said, CPI is a crucial is to be able to provide a reliable Tanzania report of its economic performance on a regular basis. According to them, IMF wants to make sure that the CPI is collected in a reliable manner as misreporting of financial data is a serious breach of confidence between it and Tanzania.

The World Bank is interested because it is has agreed to give a whopping $30 million (nearly Sh40 billion) credit to help strengthen statistics in the country.

Like Mr Kwesigabo, the World Bank expert said he sees no political motive in the new approach. He said the proposed changes aim to indicate consumers' changes in choices with regard to how and where they spend their money under existing economic circumstances.

The new system also proposes to increase the weight of transport from 9.7 to 11.1 per cent whereas the weights of health and education are to drop from 2.1 per cent and 2.6 to one per cent and 1.5 respectively. New additions in the CPI basket include spending on mobile phone recharge vouchers.

The cost of living hit double digits in September 2008 for the first time in a decade and has not eased since then, but it decreased to 12.2 per cent last month from the November level of 12.5 per cent.

The review is also meant to make the country's formula compatible with that of the all members of the Southern Africa  Development Community (SADC).

Additional reporting by Damas Kanyabwoya