decompose_change
Splits the change in the value of a named indicator or of an HS code into a unit-value (price) effect and a volume effect: the latest window of 1, 3 or 12 months (default 12) is compared with the same months a year earlier, with the log-mean (LMDI) method, so the two effects add up to the change in value exactly (check shows the residual). The answer gives value, quantity and unit value for both windows in the reporter currency and in US dollars. Give either "indicator" (an id or alias from list_indicators; only indicators that have a quantity measure can be split, others answer decomposition_not_applicable) or "reporter", "flow" and "code" (HS code of 2, 4 or 6 digits or the national code; "country" for one partner). Use it for questions such as how much of a change in imports or exports came from a higher unit value and how much from a larger quantity. The unit value is value divided by quantity, a calculation that also reflects product mix, not a price index; in US dollars the exchange-rate movement is part of the price effect; the split describes the numbers and does not show causes. A window with a missing month, a missing weight or a zero quantity is returned as null with a reason, never as a zero effect. Reference information computed mechanically from public statistics; not investment advice, a credit rating or a trading recommendation.
Tool call template
This tool declares no required parameters. Add optional parameters from the input schema as needed.
{
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"method": "tools/call",
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"arguments": {},
"name": "decompose_change"
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}Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| code | No | HS product code of 2, 4 or 6 digits or the national code of the reporter; dots are ignored (for example "850760"). Give this (with reporter and flow) or indicator, not both. | |
| flow | No | import or export. Required with code; not used with indicator. | |
| month | No | Optional. The last month of the window, YYYY-MM; default the latest month. The window and the year-earlier window must lie inside your history. | |
| window | No | Months in the window compared with the same months a year earlier: 1, 3 or 12 (default 12). | |
| country | No | Optional, codes only. Partner country as an ISO alpha-2 code or a name; omit for the world total. | |
| quantity | No | The quantity that the unit value divides by: "kg" (weight, default) or "qty" (the unit of the product, only where it is a single unit; otherwise null with mixed_units). Indicators answer quantity from kg only; "qty" applies to an HS code. | |
| reporter | No | The reporting country (JP, US, GB or EU). Required with code; not used with indicator. | |
| component | No | Optional, indicators only. The component to split when the indicator has several; the default is the one its definition names. | |
| indicator | No | The indicator id (for example "jp.naphtha.import_unit_price"), an alias in English or Japanese, or a few distinctive words; see list_indicators. Give this or code, not both. |