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AI-GEOSTATS: Significant Moran's I?

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  • Russell Barbour
    To measure auto-coorelation Moran s I is compared to the expected I that would be generated from a random distribution. My question is if the observed
    Message 1 of 2 , Jul 10, 2003
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      To measure auto-coorelation Moran's I is compared to the expected "I" that
      would be generated from a random distribution. My question is if the observed
      Moran's I is more than one standard deviation higher than expected "I" could
      that be considered significant auto-correlation?

      Thanks
      Russell Barbour Ph.D.
      Research Associate in Applied Mathematics
      Vector Ecology Laboratory
      Yale School of Medicine
      60 College St. Rm 600
      New Haven CT. 06520
      TEL: 203 785 3223
      FAX 203 785 3604
      email: russell.barbour@...




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    • Roger Bivand
      ... I guess that will depend on your specific application. If you permute your observed values about your spatial units, you can work out how far out in one of
      Message 2 of 2 , Jul 24, 2003
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        On Thu, 10 Jul 2003, Russell Barbour wrote:

        > To measure auto-coorelation Moran's I is compared to the expected "I" that
        > would be generated from a random distribution. My question is if the observed
        > Moran's I is more than one standard deviation higher than expected "I" could
        > that be considered significant auto-correlation?

        I guess that will depend on your specific application. If you permute your
        observed values about your spatial units, you can work out how far out in
        one of the tails your observed statistic falls. Where you want to set your
        bound for a significant statistic is then a matter for your judgement,
        although +1SD sounds permissive. Recall that Moran's I can also detect
        non-stationarity, so is a general test for spatial mis-specification
        (Fingleton, 1999, Journal of Regional Science).

        Roger Bivand

        >
        > Thanks
        > Russell Barbour Ph.D.
        > Research Associate in Applied Mathematics
        > Vector Ecology Laboratory
        > Yale School of Medicine
        > 60 College St. Rm 600
        > New Haven CT. 06520
        > TEL: 203 785 3223
        > FAX 203 785 3604
        > email: russell.barbour@...
        >

        Economic Geography Section, Department of Economics, Norwegian School of
        Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
        Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
        e-mail: Roger.Bivand@...


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