low Cronbach's alpha

[Elsy George]

Hi,

I am currently in the initial stage of my research and don't have much experience in statistical analysis. This might be a very basic question
I am doing analysis based on my survey to find out gender vulnerability. For that I have created a composite Gender vulnerability index using using 4 indices human capital index, physical capital index, financial capita index and social capital index. While checking for scale reliability I am getting very low cronbachs alpha. I am not getting any solution to this problem. It will be really helpful to clarify this issue.

egen hci = rsum( education canswim )
egen pci = rsum( entryoffloodwater accesstofloodshelter )
egen sci = rsum( receivedwarnings reliefmaterialrecieved )
egen fci = rsum( ownhouse ownland owngold ownvehicle ownlivestock havesavings )
egen gvi = rsum( hci pci sci fci )

input byte(education canswim ownhouse ownland ownglod ownvehicle ownlivestock havesavings receivewarnings reliefmaterialrecieved entryoffloodwater accesstofloodshelter)
2 1 1 1 0 1 0 1 1 1 3 1
3 0 1 0 1 0 0 1 1 1 3 1
2 1 0 0 0 1 0 1 0 2 1 1
4 0 1 1 1 0 1 1 0 2 1 1
3 1 1 1 0 1 0 1 0 1 1 1
2 0 1 0 1 0 1 1 0 1 1 1
1 1 1 1 0 0 0 0 0 1 3 1
3 1 1 0 0 0 0 1 0 1 3 1
1 1 0 1 0 1 0 1 0 1 1 1
5 0 1 0 0 0 1 1 0 1 1 1
3 1 1 1 1 0 0 1 1 2 1 1
2 1 1 0 0 0 1 1 1 2 1 1
4 1 0 1 0 1 0 1 0 0 3 2
2 0 1 0 0 0 0 0 0 0 3 2
1 1 0 1 0 0 0 1 0 1 3 1
3 0 1 1 1 0 1 1 0 1 3 1
1 1 0 1 0 0 0 1 0 1 3 2
3 0 1 1 1 0 1 1 0 1 3 2
4 1 1 1 0 1 0 1 0 1 1 1
3 0 0 0 1 0 0 0 0 1 1 1
1 1 1 1 0 1 0 1 0 0 3 1
3 0 0 0 1 0 0 1 0 0 3 1
3 1 1 1 0 1 0 1 0 2 1 1
2 0 1 1 1 0 1 1 0 2 1 1
3 1 1 1 0 1 0 1 0 1 1 1
2 1 1 0 1 0 1 1 0 1 1 1
4 1 1 1 0 0 0 1 1 1 1 1
3 0 0 0 0 0 1 1 1 1 1 1
1 1 0 0 0 1 0 1 0 1 3 2
3 0 1 0 0 0 0 1 0 1 3 2
4 1 1 1 0 1 0 1 0 1 3 2
3 0 0 0 1 0 0 1 0 1 3 2
2 0 1 0 1 0 0 1 0 0 3 1
3 1 1 1 0 1 0 1 0 1 1 1
2 0 1 0 1 0 1 1 0 1 1 1
4 0 1 1 0 0 0 1 0 1 1 1
3 0 1 0 1 0 1 1 0 1 1 1
3 0 1 1 0 0 0 1 0 1 3 1
2 0 1 0 0 0 0 1 0 1 3 1
3 0 1 1 0 0 0 1 0 1 1 1
3 1 1 1 0 1 0 1 0 1 1 1
2 0 0 0 1 0 0 0 0 1 1 1
3 1 1 1 0 1 0 1 0 1 3 1
2 1 1 1 1 0 1 1 0 1 3 1
2 1 1 1 0 1 0 1 0 2 1 1
1 0 0 0 1 0 0 0 0 2 1 1
3 0 1 1 0 1 0 1 0 2 3 1
2 0 0 0 1 0 0 0 0 2 3 1
3 1 1 1 0 1 0 1 0 0 3 2
1 0 0 0 1 0 1 1 0 0 3 2
4 0 1 1 0 0 1 1 0 1 3 1
3 1 1 1 0 1 0 1 0 2 1 1
2 0 1 0 1 0 1 1 0 2 1 1
3 1 1 1 0 1 0 1 1 1 1 1
2 0 1 0 0 0 0 0 1 1 1 1
3 1 1 1 0 1 0 1 0 1 1 1
2 0 0 0 0 0 0 0 0 1 1 1
3 1 1 1 0 1 0 1 1 1 1 2
2 0 0 0 1 0 1 1 1 1 1 2
3 0 1 1 0 0 0 0 0 1 1 1
2 1 1 1 0 1 0 1 1 1 1 1
1 0 0 0 0 0 0 0 1 1 1 1
4 1 1 1 0 1 0 1 1 1 1 1
2 0 0 0 0 0 0 0 1 1 1 1
1 1 1 1 0 1 0 1 1 1 1 1
2 0 1 0 1 0 0 0 1 1 1 1
3 1 1 1 0 1 0 1 1 1 1 1
4 0 0 0 0 0 0 0 1 1 1 1
3 1 1 1 0 0 1 1 0 1 1 1
1 1 1 1 0 1 0 1 0 1 1 1
2 1 1 0 1 0 1 1 0 1 1 1
1 1 1 1 0 1 0 1 0 1 3 1
2 1 0 0 1 0 1 1 0 1 3 1
3 1 1 1 0 1 0 1 0 1 1 1
2 1 1 0 1 0 0 1 0 1 1 1
1 1 1 1 0 1 0 1 0 1 3 2
1 0 1 0 1 0 0 1 0 1 3 2
3 1 1 1 0 1 0 1 0 1 1 2
2 0 0 0 1 0 1 1 0 1 1 2
3 1 1 1 0 0 0 1 0 1 3 1
2 0 1 0 1 0 1 1 0 1 3 1
1 1 0 1 0 1 0 1 0 1 3 2
3 0 1 1 1 0 1 1 0 1 3 2
1 1 0 1 0 0 0 1 0 1 3 1
3 0 0 1 1 0 1 1 0 1 3 1
2 1 1 1 0 1 0 1 0 1 1 1
3 1 1 0 1 0 1 1 0 1 1 1
2 1 0 0 0 1 0 1 0 1 1 1
4 0 0 1 0 0 0 1 0 1 1 1
2 1 1 1 0 1 0 1 0 1 1 1
3 0 1 0 1 0 0 1 0 1 1 1
2 1 0 1 0 1 0 1 0 1 3 2
1 1 0 1 1 0 1 1 0 1 3 2
3 0 1 1 1 0 1 1 0 1 3 2
3 0 1 1 0 0 1 1 0 1 1 1
2 1 1 1 0 1 0 1 0 1 1 1
3 1 0 0 1 0 1 1 0 1 1 1
1 1 0 1 0 1 0 1 0 0 3 2
4 0 1 1 1 0 1 1 0 0 3 2
4 1 1 1 0 1 0 1 0 2 1 2
end

Thank you

[Joseph Coveney]

While checking for scale reliability I am getting very low cronbachs alpha. I am not getting any solution to this problem. It will be really helpful to clarify this issue.

I don't know what the individual item prompts are, but it looks as if at least part of your problem are that your scale is not unidimensional and that one of the components (viz., physical capital) loads in the opposite direction from others (see below), which militates against a simple summing of the intermediate sumscores.

Also, consider whether it's advisable to just sum item responses whose ranges (number of categories) differ.

.ÿ
.ÿversionÿ17.0

.ÿ
.ÿclearÿ*

.ÿ
.ÿquietlyÿinputÿbyte(educationÿcanswimÿownhouseÿownlandÿowngoldÿownvehicleÿ///
>ÿÿÿÿÿÿÿÿÿownlivestockÿhavesavingsÿreceivedwarningsÿreliefmaterialrecievedÿ///
>ÿÿÿÿÿÿÿÿÿentryoffloodwaterÿaccesstofloodshelter)

.ÿ
.ÿ/*ÿhumanÿcapitalÿindex
>ÿÿÿÿphysicalÿcapitalÿindex
>ÿÿÿÿfinancialÿcapitaÿindex
>ÿÿÿÿsocialÿcapitalÿindexÿ*/
.ÿegenÿbyteÿhciÿ=ÿrowtotal(educationÿcanswim)ÿ

.ÿegenÿbyteÿpciÿ=ÿrowtotal(entryoffloodwaterÿaccesstofloodshelter)

.ÿegenÿbyteÿfciÿ=ÿrowtotal(ownhouseÿownlandÿowngoldÿownvehicleÿownlivestockÿhavesavings)

.ÿegenÿbyteÿsciÿ=ÿrowtotal(receivedwarningsÿreliefmaterialrecieved)

.ÿ//ÿegenÿbyteÿgviÿ=ÿrowtotal(hciÿpciÿsciÿfci)
.ÿ
.ÿpolychoricÿ??i

Polychoricÿcorrelationÿmatrix

ÿÿÿÿÿÿÿÿÿÿÿÿhciÿÿÿÿÿÿÿÿÿpciÿÿÿÿÿÿÿÿÿfciÿÿÿÿÿÿÿÿÿsci
hciÿÿÿÿÿÿÿÿÿÿÿ1
pciÿÿÿ-.2356342ÿÿÿÿÿÿÿÿÿÿÿ1
fciÿÿÿ.36981472ÿÿÿ.08694733ÿÿÿÿÿÿÿÿÿÿÿ1
sciÿÿÿÿ.0846484ÿÿ-.63412317ÿÿ-.04537374ÿÿÿÿÿÿÿÿÿÿÿ1

.ÿtempnameÿRho

.ÿmatrixÿdefineÿ`Rho'ÿ=ÿr(R)

.ÿlocalÿNÿ=ÿr(N)

.ÿ
.ÿfactormatÿ`Rho',ÿn(`N')ÿfactors(2)ÿblanks(0.3)
(obs=100)

Factorÿanalysis/correlationÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿNumberÿofÿobsÿÿÿÿ=ÿÿÿÿÿÿÿÿ100
ÿÿÿÿMethod:ÿprincipalÿfactorsÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿRetainedÿfactorsÿ=ÿÿÿÿÿÿÿÿÿÿ2
ÿÿÿÿRotation:ÿ(unrotated)ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿNumberÿofÿparamsÿ=ÿÿÿÿÿÿÿÿÿÿ6

ÿÿÿÿ--------------------------------------------------------------------------
ÿÿÿÿÿÿÿÿÿFactorÿÿ|ÿÿÿEigenvalueÿÿÿDifferenceÿÿÿÿÿÿÿÿProportionÿÿÿCumulative
ÿÿÿÿ-------------+------------------------------------------------------------
ÿÿÿÿÿÿÿÿFactor1ÿÿ|ÿÿÿÿÿÿ1.12373ÿÿÿÿÿÿ0.57349ÿÿÿÿÿÿÿÿÿÿÿÿ0.8987ÿÿÿÿÿÿÿ0.8987
ÿÿÿÿÿÿÿÿFactor2ÿÿ|ÿÿÿÿÿÿ0.55024ÿÿÿÿÿÿ0.67182ÿÿÿÿÿÿÿÿÿÿÿÿ0.4401ÿÿÿÿÿÿÿ1.3388
ÿÿÿÿÿÿÿÿFactor3ÿÿ|ÿÿÿÿÿ-0.12158ÿÿÿÿÿÿ0.18048ÿÿÿÿÿÿÿÿÿÿÿ-0.0972ÿÿÿÿÿÿÿ1.2416
ÿÿÿÿÿÿÿÿFactor4ÿÿ|ÿÿÿÿÿ-0.30206ÿÿÿÿÿÿÿÿÿÿÿÿ.ÿÿÿÿÿÿÿÿÿÿÿ-0.2416ÿÿÿÿÿÿÿ1.0000
ÿÿÿÿ--------------------------------------------------------------------------
ÿÿÿÿLRÿtest:ÿindependentÿvs.ÿsaturated:ÿÿchi2(6)ÿÿ=ÿÿÿ75.00ÿProb>chi2ÿ=ÿ0.0000

Factorÿloadingsÿ(patternÿmatrix)ÿandÿuniqueÿvariances

ÿÿÿÿ-------------------------------------------------
ÿÿÿÿÿÿÿÿVariableÿ|ÿÿFactor1ÿÿÿFactor2ÿ|ÿÿÿUniquenessÿ
ÿÿÿÿ-------------+--------------------+--------------
ÿÿÿÿÿÿÿÿÿÿÿÿÿhciÿ|ÿÿÿÿÿÿÿÿÿÿÿÿÿ0.5073ÿ|ÿÿÿÿÿÿ0.6748ÿÿ
ÿÿÿÿÿÿÿÿÿÿÿÿÿpciÿ|ÿÿ-0.7535ÿÿÿÿÿÿÿÿÿÿÿ|ÿÿÿÿÿÿ0.4289ÿÿ
ÿÿÿÿÿÿÿÿÿÿÿÿÿfciÿ|ÿÿÿÿÿÿÿÿÿÿÿÿÿ0.5232ÿ|ÿÿÿÿÿÿ0.7263ÿÿ
ÿÿÿÿÿÿÿÿÿÿÿÿÿsciÿ|ÿÿÿ0.6986ÿÿÿÿÿÿÿÿÿÿÿ|ÿÿÿÿÿÿ0.4962ÿÿ
ÿÿÿÿ-------------------------------------------------
ÿÿÿÿ(blanksÿrepresentÿabs(loading)<.3)

.ÿrotateÿ,ÿvarimaxÿblanks(0.3)

Factorÿanalysis/correlationÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿNumberÿofÿobsÿÿÿÿ=ÿÿÿÿÿÿÿÿ100
ÿÿÿÿMethod:ÿprincipalÿfactorsÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿRetainedÿfactorsÿ=ÿÿÿÿÿÿÿÿÿÿ2
ÿÿÿÿRotation:ÿorthogonalÿvarimaxÿ(Kaiserÿoff)ÿÿÿÿNumberÿofÿparamsÿ=ÿÿÿÿÿÿÿÿÿÿ6

ÿÿÿÿ--------------------------------------------------------------------------
ÿÿÿÿÿÿÿÿÿFactorÿÿ|ÿÿÿÿÿVarianceÿÿÿDifferenceÿÿÿÿÿÿÿÿProportionÿÿÿCumulative
ÿÿÿÿ-------------+------------------------------------------------------------
ÿÿÿÿÿÿÿÿFactor1ÿÿ|ÿÿÿÿÿÿ1.10784ÿÿÿÿÿÿ0.54172ÿÿÿÿÿÿÿÿÿÿÿÿ0.8860ÿÿÿÿÿÿÿ0.8860
ÿÿÿÿÿÿÿÿFactor2ÿÿ|ÿÿÿÿÿÿ0.56612ÿÿÿÿÿÿÿÿÿÿÿÿ.ÿÿÿÿÿÿÿÿÿÿÿÿ0.4528ÿÿÿÿÿÿÿ1.3388
ÿÿÿÿ--------------------------------------------------------------------------
ÿÿÿÿLRÿtest:ÿindependentÿvs.ÿsaturated:ÿÿchi2(6)ÿÿ=ÿÿÿ75.00ÿProb>chi2ÿ=ÿ0.0000

Rotatedÿfactorÿloadingsÿ(patternÿmatrix)ÿandÿuniqueÿvariances

ÿÿÿÿ-------------------------------------------------
ÿÿÿÿÿÿÿÿVariableÿ|ÿÿFactor1ÿÿÿFactor2ÿ|ÿÿÿUniquenessÿ
ÿÿÿÿ-------------+--------------------+--------------
ÿÿÿÿÿÿÿÿÿÿÿÿÿhciÿ|ÿÿÿÿÿÿÿÿÿÿÿÿÿ0.5436ÿ|ÿÿÿÿÿÿ0.6748ÿÿ
ÿÿÿÿÿÿÿÿÿÿÿÿÿpciÿ|ÿÿ-0.7527ÿÿÿÿÿÿÿÿÿÿÿ|ÿÿÿÿÿÿ0.4289ÿÿ
ÿÿÿÿÿÿÿÿÿÿÿÿÿfciÿ|ÿÿÿÿÿÿÿÿÿÿÿÿÿ0.5158ÿ|ÿÿÿÿÿÿ0.7263ÿÿ
ÿÿÿÿÿÿÿÿÿÿÿÿÿsciÿ|ÿÿÿ0.7098ÿÿÿÿÿÿÿÿÿÿÿ|ÿÿÿÿÿÿ0.4962ÿÿ
ÿÿÿÿ-------------------------------------------------
ÿÿÿÿ(blanksÿrepresentÿabs(loading)<.3)

Factorÿrotationÿmatrix

ÿÿÿÿ--------------------------------
ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ|ÿFactor1ÿÿFactor2ÿ
ÿÿÿÿ-------------+------------------
ÿÿÿÿÿÿÿÿÿFactor1ÿ|ÿÿ0.9861ÿÿÿ0.1664ÿ
ÿÿÿÿÿÿÿÿÿFactor2ÿ|ÿ-0.1664ÿÿÿ0.9861ÿ
ÿÿÿÿ--------------------------------

.ÿ
.ÿexit

endÿofÿdo-file


.

[Joseph Coveney]

Sorry, forgot to mention: -polychoric- is user-written and can be found by

search polychoric

[Elsy George]

Your advice was very helpful. Thanks.