Additionally, two different methods could be in play at once which needs coordination.

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The two different methods to measure fuel economy could coexist, he said.

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These are, in effect, two baskets comprising different goods and services, and different methods are used to calculate them.

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But in fact, the main reason for the two indices rising at different rates is because they use different arithmetical methods for calculating average prices.

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While the two professors' work has much in common at an "abstract level, " their methods are different, Ellingsen said.

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