-
united Sun••
Department of
Agrl(Uclture
ResearchoiWnd
Applications
Division
Evaluation. of MOI;1~i~ y
Corn Yie,lidlnClJicati,Qi'
..
anti Forecast~:'!:!::il, ..,
SRBStaffReport
Ga ry Keoug h
Number SRB-89-05
March 1989
E:VALUATl:ON OFI(ON't'HLY
CORN YIle:t,D
IN'DICATIONS
.A,NDFORECAS,"rS"
by
Ga.ry
.KGlc~ugh, Research
and .Applications Di.vlsiclfl,Net,ic>nal
A,qri.cul tUJ:al Statistics
Service:", U.s. Department of Agriculture
I
W.ashlngton, D.C.
20250, January 1989.
Staff Report. No. SRB-89-
04
DSTRACT
This report
ex.a•.ines
the estimated
accuracy of several monthly
corn yield surv'elY' indio:ations and composite forecasts for the 10
corn Objective Yield States from 1977 to 1986.
Indications
adjusted for an estimated bias produced more accurate forecasts
th~!l:nunadjusted
indications
about 85 percent,
of 1;be time"'
C"ompOlilit:,e
forecasts
perfiornlE:~d a.s. well
(rr' bet:ter
than the
1\ I'"''
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"I
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ij,., 1.11. O.
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'.
,:.,
••• 1.""
...1 """""
a,a "..1".11 ..
oIl,,,;:~ ..
"". ",1.1: .. ,," t•.a. ,S
"i::>
,t·I.,tl~:1U:::>'_,
S"t:~!ptetl1lheJr. I and. OctOI:lI!i::~::~:',
NCI ()!le
(:~O:I!!IPC)I:Si.i.·t::C"
hO!N'e"'VE!:r
,I'
<;::C;JrlS,i~:itE;:r.1:1y
c.~utpl~rforlJjedthe AS13fo:recl:u"t::s.
T];u!~f\S(:l:t'o:r:(!:ca::i,t,
(:)utp(n:'fClrmc:~d
all
cltber
f:():t'""Gas'l:.l:=:
.ii"'[ NOV'!:!il[Ri::I'lar",
'I'h'i~nOllpI"obab.ili.ty
based
Acreage and P::~:"od\lcti\::jln yield indication
approxim.ates the fi.nal
ASByield
e.st.:i'''i.:a.t~e tJ':ueilest
in five. states
1 while
the Novembex'
ASB foreca.st
.:t"s best
,:In f(Jur states.
:R''?(;:~::UiUitIE::rI"d
..at:LC::i]II:''IISar'e~
The composi
te
Gorl~~, i
in~l
I:)f
th~;a b.:L:1S
,a.dju$1I::edl
:f'ar':l1[I,I!~::t" Reported
Yield
and Daily' Weathertl.f<!><:lelYie:ld
ind,ication
should be available.
forl~g8 ..,A"uqust: 1for(~cast;
review;
The composite consisting
of
the biasa.Qjust.ed
Farmer Reported
Yield artd Objective Y.