Goddard Building, University of Queensland, St Lucia Qld 4072
tsx@uq.edu.au

How do I know how good my index is?

You can produce a Threatened Species Index tailored to your specific needs if you visit the web visualization tool. So far, you can choose a bird group, sub-group, state/territory or a combination thereof. You can even create a trend for those birds listed as National Priority Species on the Australian Government’s Threatened Species Strategy.

But be careful – some trends are more reliable than others. An index will always be as good as the data it gets. For example, our national Threatened Bird Index is quite representative of the eastern states but not as representative for Western Australia, the Northern Territory and the arid zone. We just don’t have much data in these places, as many of the locations are quite remote.

We have developed diagnostics that you can use to understand how representative each trend is. There are a few steps that you can follow to understand how good your trend is:

  1. Select the combination of possible attributes for which you want to produce a trend.
  2.  
    Index graph showing declining trendline between 1985 and 2005
     

  3. Look at the Spatial representativeness map to see how much data there are and where these data come from. Compare this with what you might know of the distributions of species/subspecies within the index you have calculated.
  4. Map of Australia with dots showing higher concentrations of data in southern, eastern and coastal regions
     

  5. Look at Monitoring consistency to see how consistently each monitoring location was visited over time. Each row represents a time series where a species/subspecies was monitored with a consistent method at a single site.
    Graph of monitoring frequency over time showing higher concentrations of monitoring data in recent years
     
  6. Go to Time series and species accumulation plot to see how many time series and species/subspecies were used to calculate this index in each year. Are there really enough data for the reference year that you selected? Remember that we can’t produce any trends for less than 3 species/subspecies.
    Graph showing number of taxa and time series peaking between 2000 and 2020
     
  7. Adjust the Reference year to let the index start at a year with more data.

     

  8. Go to Data Summary to see which species/subspecies were included in this index

     

  9. Go to Download CSV to get the aggregated data used to calculate this index.
     
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