Tuesday, October 20, 2009

Why no corrected number for soybeans this week?

The closer I get to harvest, the more observations I'm missing for that week when I calculate my 'correction'. This is because the last date the condition information is published depends on harvest progress. So, if I publish a SOYBEAN correction this week it would be with only a handful of observations. In the US report, I'd only have conditions for this week in 1990, 1992 and 1993. This is clearly related to the delayed harvest we are undergoing.

I probably should have gone ahead and published the correction, but it would require a bit of an explanation. Let me go ahead and do that and see if you readers out there think it should be investigated further. So with potentially fewer observations (not calculated how many) the adjustment this week would be significant. I'd be down to 41.2 bushels an acre. Down about a full bushel from last week. The adjustment in Iowa and Illinois would be about 2 bu/ac. This the last week I'd get any adjustment at all, we have not had bean conditions past week 29 in my calendar

Now it could simply be some fluke of the small number of observations available this late in the year or it could be that conditions tend to significantly over estimate yields when harvest is delayed, or the delay itself results in lower yields. I certainly don't have enough information to draw any conclusion.

It also looks like I trimmed off LAST weeks soybean corrected numbers, so here they are again for completeness. They do NOT include this weeks adjustment with just three observations.

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