Complementary strategies double the impact of cost-effective ranked strategies

Our manuscript on how complementarity can help saving more species per dollar spent is available online. If you are interested in cost-effectiveness analysis, PPP (Project Prioritisation Protocol), priority threat management, expert elicitations, or the Pilbara, have a look:

Chades, I., Nicol, S., van Leeuwen, S., Walters, B., Firn, J., Reeson, A., Martin, T. G. . and Carwardine, J. (2014), Benefits of integrating complementarity into priority threat management. Conservation Biology. doi: 10.1111/cobi.12413 (abstract) (request pdf)

In Tulloch et al (2013), we studied how complementarity could help choosing indicator species to improve our monitoring power, Chades et al (2014) explores further this idea in the context of priority threat management. Feel free to download the Pilbara report for details about the study.

Priority threat management process requires a strong collaborative team to be successful. This manuscript is a great example of a work that would not have been possible without the essential contribution of all authors.

Abstract:Figure2_manuscript_R1_with legend_rgb

Conservation decision tools based on cost-effectiveness analysis are used to assess threat management strategies for improving species persistence. These approaches rank alternative strategies by their benefit to cost ratio but may fail to identify the optimal sets of strategies to implement under limited budgets because they do not account for redundancies. We devised a multiobjective optimization approach in which the complementarity principle is applied to identify the sets of threat management strategies that protect the most species for any budget. We used our approach to prioritize threat management strategies for 53 species of conservation concern in the Pilbara, Australia. We followed a structured elicitation approach to collect information on the benefits and costs of implementing 17 different conservation strategies during a 3-day workshop with 49 stakeholders and experts in the biodiversity, conservation, and management of the Pilbara. We compared the performance of our complementarity priority threat management approach with a current cost-effectiveness ranking approach. A complementary set of 3 strategies: domestic herbivore management, fire management and research, and sanctuaries provided all species with >50% chance of persistence for $4.7 million/year over 20 years. Achieving the same result cost almost twice as much ($9.71 million/year) when strategies were selected by their cost-effectiveness ranks alone. Our results show that complementarity of management benefits has the potential to double the impact of priority threat management approaches.


Analyzing, discussing and revising experts’ opinion via an anonymous online forum: video

Today, we are launching our ‘albopictus’ online forum to allow our experts to analyze, discuss and revise their opinion while remaining anonymous. This project is about providing guidance on which pathways to manage in priority to reduce the risk of infestation of mainland Australia by the invasive mosquito aedes Albopictus. Our experts are based in different locations across Australia and Asia. When asked if they would be willing to participate to such ‘online forum’, all experts responded positively. It is now time to check if we can use that tool for future expert elicitation exercises.

The need for anonymous discussion prompted us to use a web forum rather than emails. Setting up the forum has been time consuming and we are still learning how to make it clearer for non-nerdy experts. It’s also easy to assess how many experts actually went to the forum or contributed.

Chrystal has recorded a video to help our experts. Have a look. Fingers crossed. I will report on this experience in 2 weeks time!



Eliciting expert opinion and the 4-point estimates method

I’m currently involved in 3 projects where data is not available but we still need to provide guidance to managers on what action will be most efficient. In such cases, we have no choice but eliciting information from experts. There are many ways of proceeding, and you can find relevant information on google, but I still find that the details of how exactly doing it isn’t written anywhere. I feel that there is a big part of non-written way of proceeding that would benefit many of us. So if you are an expert in expert elicitation, please write us a guide – e.g. not another review!

For example we had trouble using 4-point estimates* data, and explaining to our experts what the confidence value represented. We did explain it many times, but we still get errors when we analyze the data. I do feel sorry for our experts that constantly have to rethink their values.

Beta distribution corresponding to the 4-point estimates
Beta distribution corresponding to the 4-point estimates

With internship student Martin Peron, we have developed a program to fit beta distribution to 4-point estimates. We are hoping to submit this program to MATLAB exchange very soon (and GNU Octave). So stay tuned if you are looking for such a program!

* 4 point estimates: best guess, min, max and confidence that the true value of the parameter we are estimating lies in this interval.

Expert elicitation and priority threat management in the Pilbara

This year, our team has been working on a cost benefit analysis project to determine the priority threat management options to protect the listed species of the Pilbara, WA.

Part of our project consists in gathering data from different sources, published and grey literature, and most importantly experts knowledge. We ran an anonymous expert elicitation workshop in March 2013 to gather the critical information needed for our project.

When running an expert elicitation exercise it is recommended that experts remain anonymous so that bias is limited when collecting the expert knowledge (benefit estimates, in this case). Once the preliminary analysis is done and individual mistakes are corrected, it is important to provide a way of discussing the results as a group so that additional information can be exchanged and informed discussion can lead to less divergence in opinions.

To set up that discussion phase and maintain an anonymous process, we have set up a forum for our experts to comment and discuss the current group trends and divergence. We’ve had a couple of responses to our forum from contributors who said that they’d appreciate more information about how to use the forum. In response I recorded a quick video that captures my screen as I go through the features of the forum. The video is available on YouTube, and can be accessed at the link below. You can play this video full screen and you can also increase the quality to High Definition (HD).