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help > RE: Reporting Results T-Value
Mar 29, 2017 02:03 AM | Alfonso Nieto-Castanon - Boston University
RE: Reporting Results T-Value
Hi Jennifer,
Typically you would just report the combination of voxel-level "height" threshold (some times also referred to as "cluster-defining" or "cluster-forming" threshold; voxel-level uncorrected p<.001) and the cluster-level "extent" threshold (e.g. cluster-level p-FDR<.05) used to identify significant clusters. In the results explorer window these are the two p-value thresholds specified at the top of this figure.
It is not a bad idea to also report for each individual cluster a measure of its location (e.g. the MNI coordinates of the peak voxel, listed in the mid-figure list under the "(x,y,z)" column) as well as measures of each cluster size (listed under "size") and associated cluster-size p-values (e.g. under "size p-FDR" or "size p-FWE" in the same list).
Last, it is best if you can also report measures of effect-size within each cluster. These depend on the nature of your analyses, for example if you are looking at differences in connectivity between two groups it is a good idea to report within each cluster the average connectivity values within each group and/or the differences in connectivity between the two groups. For these you typically would go to "plot effects" and report the values listed under "beta" in the resulting plots (but this depends a bit on your specific analyses)
Hope this helps
Alfonso
Originally posted by Jennifer Siegel :
Typically you would just report the combination of voxel-level "height" threshold (some times also referred to as "cluster-defining" or "cluster-forming" threshold; voxel-level uncorrected p<.001) and the cluster-level "extent" threshold (e.g. cluster-level p-FDR<.05) used to identify significant clusters. In the results explorer window these are the two p-value thresholds specified at the top of this figure.
It is not a bad idea to also report for each individual cluster a measure of its location (e.g. the MNI coordinates of the peak voxel, listed in the mid-figure list under the "(x,y,z)" column) as well as measures of each cluster size (listed under "size") and associated cluster-size p-values (e.g. under "size p-FDR" or "size p-FWE" in the same list).
Last, it is best if you can also report measures of effect-size within each cluster. These depend on the nature of your analyses, for example if you are looking at differences in connectivity between two groups it is a good idea to report within each cluster the average connectivity values within each group and/or the differences in connectivity between the two groups. For these you typically would go to "plot effects" and report the values listed under "beta" in the resulting plots (but this depends a bit on your specific analyses)
Hope this helps
Alfonso
Originally posted by Jennifer Siegel :
Hello,
I just want to clarify something in regards to reporting my results. How do I obtain the individual T values for each significant cluster?
I notice there is a T-value listed at the top of the results page, but this is the same for all the clusters. I assume that this isn't what I want to report.
When I go into the "display values option", I see a cluster T-value, but the cluster p-FDR result is different to the results cluster p-FDR (and the order of my clusters changes slightly). Which one do I report and why are these different?
Thanks,
Jennifer
Disregard my attachment, it wouldn't let me delete it.
I just want to clarify something in regards to reporting my results. How do I obtain the individual T values for each significant cluster?
I notice there is a T-value listed at the top of the results page, but this is the same for all the clusters. I assume that this isn't what I want to report.
When I go into the "display values option", I see a cluster T-value, but the cluster p-FDR result is different to the results cluster p-FDR (and the order of my clusters changes slightly). Which one do I report and why are these different?
Thanks,
Jennifer
Disregard my attachment, it wouldn't let me delete it.
Threaded View
| Title | Author | Date |
|---|---|---|
| Jennifer Siegel | Mar 28, 2017 | |
| Alfonso Nieto-Castanon | Mar 29, 2017 | |
| Jennifer Siegel | Mar 31, 2017 | |
| Alfonso Nieto-Castanon | Mar 31, 2017 | |
| Jennifer Siegel | Apr 14, 2017 | |