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CALCULATING THE RELIABILITY INTRACLASS CORRELATION COEFFICIENT
AND IReference: Hopkins WG (2009). Calculating the reliability
intraclass correlation coefficient an its c
'he &CC here is the one that gies the sa!e alue as the
testretest *earson correlation for large s
(-or s!all sa!ples the *earson is slightly biase+ but the
&CC is unbiase.)
ou $ill also nee the nu!ber of sub/ects an the egrees of
freeo! of the $ithinsub/ect 1.
ou $ill also nee the nu!ber of sub/ects an the nu!ber of tests.
&f there are !issing alues+ y
(When there are no !issing alues+ the nu!ber of entries is the
nu!ber of sub/ects ti!es the nu
se ata fro! a t$o$ay 34563 $ith sub/ects an tests as the t$o
effects an no interaction.
se the - statistic for the sub/ects ter!. 1on,t use the -
for tests or the oerall -.
"nter alues of statistics $ith one !ore significant igit than
you $oul nor!ally publish+ to aoi s
'he relationship bet$een the &CC an - statistic is ue to
7artko 88 (9). 'he intraclass correlati
'he relationship is &CCine gie
&t is the nu!ber of tests that $oul gie the nu!ber of egrees
of freeo! for the $ithinsub/ect
'he for!ula for confience li!its for the &CC is ue to
>cGra$ @5 A Wong * (99). -or!ing inf
& use the for!ula for their &CC(C+)+ case ;. 'his is the
sa!e as 7artko,s &CC.
Between- and within-sube!t SD "n#wn
4 7et$een Within 1eg. Conf. &CC an confience li!itssub/ects
1 1 freeo! leel () &CC lo$er upper appro#. D
$% $ &'() $* +& &'($ &')) &'+&
&',$
DI./&0 E112%&$ E112%&$ E112%&$
ICC "n#wn3 when the1e a1e n# 4issin5 6a7ues
4 k Conf. &CC an confience li!its
sub/ects tests &CC leel () &CC lo$er upper appro#. D
$% $ &'($ +& &'($ &')) &'+& &',$
DI./&0 E112%&$ E112%&$ E112%&$
ICC "n#wn3 when the1e ARE 4issin5 6a7ues
4 k n Conf. &CC an confience li!its
sub/ects tests entries &CC leel () &CC lo$er upper
appro#. D
,( 8 %& &'9% +& &'9% &'%9 &'(9
&',%
DI./&0 E112%&$ E112%&$ E112%&$
F "n#wn3 when the1e a1e n# 4issin5 6a7ues
4 k - for Conf. &CC an confience li!its
sub/ects tests sub/ects leel () &CC lo$er upper appro#.
D
,% $ $+'$ +& &'+8 &'(* &'+9
&'&),'&& E112%&$ E112%&$ E112%&$
I: ;#u want the ICC an its confience li!its+ gien a
bet$eensub/ect 1 an a $ithinsub/ect 1:
I: ;#u ha6e the ICC an you $ant its confience li!its:
I: ;#u ha6e an F 6a7ue fro! an 34563 that you use for the
reliability analysis+ an you $ant the
Replace the nu!bers in b7ue $ith your nu!bers+ or put your
nu!bers in the blank cells unerneat
'he results are in 1ed. 1on,t !oify black nu!bers in the cells
$ith a grey backgroun.
I: ;#u1 SD a1e
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S CONFIDENCE LIMITSnfience li!its ("#cel spreasheet).
ne$stats.org%#&CC.#ls
a!ples+ $hen there are 2 tests. &t,s al!ost al$ays the one
you $ant.
u $ill also nee the nu!ber of test entries (obserations).
ber of tests.)
bstantial rouning errors.
n coefficient as a !easure of reliability. *sychological Reports
9+ ;
sts $hen there are !issing alues in one or !ore tests for one or
!ore sub/ects.
s the sa!e ans$er as *roc G?> in 3.
1 (the stanar or typical error of !easure!ent+ or the
R>" fro! an 34563).
rences about so!e intraclass correlation coefficients.
*sychological >ethos + ;0B.
"ffectieno.of tests - - lo$er - upper
2.00 9. B.9 9.
.00 I1&6%0J "rr:02 "rr:02
1eg free - - lo$er - upper
2B 9. B.9 9.
.0 "rr:02 "rr:02
"ffectie
1eg free no.of tests - - lo$er - upper
;0 2.K 9.; B.K 20.0
0.00 .0 "rr:02 "rr:02
1eg free - lo$er - upper
B . K2. "rr:02 "rr:02
:
&CC an its confience li!its:
.
you enter the!+ as follo$s:
