NAPERVILLE, Illinois, Oct 18 (Reuters) - U.S. corn yield was of prime focus during the U.S. Department of Agriculture’s biannual data users’ meeting on Wednesday, which offers market participants the chance to question the agency on items like forecasts, methodology and data accessibility.

Several attendees in the virtual meeting noted that U.S. corn yield has landed below USDA’s trend yield for five consecutive years now, prompting questions as to whether the calculation will be revisited for future seasons.

The market’s main grievance with the recent yield pattern is that negative price implications could arise if trend yield starts out too high, since it may cause U.S. corn supplies to be overstated early on.

Trend yield is set forth by USDA’s World Board and is based off a publicly documented model written in 2012. It provides a starting point for the corn crop each year and reflects what yield would be with “normal” growing season weather, accounting for expected upward adjustments over time as technology and practices improve.

Agency officials said on Wednesday that there are no plans to recalibrate yield estimates and that they evaluate the data on a year-in, year-out basis, implying their recent assumptions are up to date. They also suggested that consecutive bad weather years can skew the view of true trend yield.

Significant weather events in the U.S. Corn Belt could be identified in at least four of the last five years, but that does raise the question as to whether USDA’s expectations of “normal” weather are too idealistic. At some point, if there are more outliers than not in a dataset, then are they really outliers?

LOOKING AHEAD

USDA in May set official 2023 corn trend yield at 181.5 bushels per acre (bpa), almost 5 bpa higher than the previous record, though the latest estimate is much lower at 173 after bouts of dry weather. In the last five years including 2023, corn yield fell below trend in each year and by an average of 6.1 bpa (3.4%).

Actual yield had exceeded the trend in each of the previous five years (2014-2018) by an average of 4.4 bpa (2.6%). That includes a maximum of 6.6 bpa (3.9%) in 2016, so large jumps above the trend are neither unprecedented nor impossible.

But it does set a tall task for the 2024 U.S. corn crop as starting yield may match or exceed this year’s 181.5 bpa. Last November, the tentative trend for 2024 was set at 183.5 bpa in USDA’s annual long-term projections, which are formulated separately from the agency’s monthly supply and demand reports.

In late 2021, the 2023 yield target was listed at 183 bpa, but that came down to 181.5 in late 2022, identical to the official number set this May. In the last couple years, USDA published these tables during the first week of November, so a peek at the 2024 outlook should be just around the corner. Karen Braun is a market analyst for Reuters. Views expressed above are her own.

(Editing by Marguerita Choy)