Lab 3 In Lab 3, we'll study the use of CDA models for estimation of some IUCN risk criteria. We'll look at a number of different data sets, and look at what causes poors estimates and explore which risk metrics tend to be well measured (versus those that are poorly measured). Figure 1: Shows some diagnostics for the data and the posteriors for mu, sigma_2 (process error), and sigma2_np. The posterior is based on a uniform priors. How to interpret such a posterior for the purpose of scientific inference (e.g. assigning something equivalent to a P-value for frequentists) is up to considerable debate. Nonetheless, it represents a common currency by which we can compare the precision of CDA risk estimates for different data sets. In this lab, it is used in this sense, as a standardized metric of precision (without making any absolute inferential statements). Figure 2: Shows the posteriors for some risk metrics. How to interpret the posteriors for the purpose of this lab. Think about them as a relative measure of data support (relative to the other risk metrics and other. If most of the area of the posterior is within a particular range, that indicates that most of the data support is within that range. At the matlab prompt, you'll type 'Lab3'. You'll be asked to choose a datatype, then you'll be asked to choose a quasi-extinction level, and then a time horizon. Quasi-extinction level: 80% decline, 50% decline, or 20% decline. These correspond to the IUCN criteria A2 for critically endangered, endangered, and vunerable. Time horizon: Choose the number of years for the extinction horizon. IUCN uses 10 years or 3 generations. For this lab, we'll look at 10, 25 and 50 year horizons (you can type in other horizons if you wish though). For this exercise you'll need generations times. We'll use average age of first reproduction. Grey-headed albatrosses: 10 yr Trumpeter Swans: 5 yr White-capped albatrosses: 5 yr Northern fur seal: 4 yr Sharp-tailed grouse: 1 yr Mute swan: 3 yr Wolves: 3 yr Exercise 1: Working a case study example. At the prompt, type 'Lab3'. Input the data code for your species. Look at IUCN CR Criteria A2: Choose 80% decline, 3 x gen time horizon. Look at IUCN EN Criteria A2: Choose 50% decline, 3 x gen time horizon. Look at IUCN VU Criteria A2: Choose 20% decline, 3 x gen time horizon. Use 'edit:copy figure' in matlab, and paste these into a Word document. Upload using the 'user material' option in Chinook. Use Summarize what the information the CDA analysis gives us on long-term % increase or decline (exp(mu) x 100), and the A2 risk criteria. Comment on what can be said with little certainty versus what can be said with relative certainty -- given the data available to you. Exercise 2: Uncertainty of probability of decline estimates. Choose a % decline: 20, 50 or 80 Type 'Lab3' at the prompt. Pick a dataset. Make plots for each of 3 time horizons: 10, 25, 50 years Copy into a Word document. Do this for a few other datasets. Summarize what you see in terms of how precisely the probability of decline is estimated and whether uncertainty at one time horizon translates into uncertainty at other time horizons.