# Environmetrics Australia > Environment ● Statistics ● Science ## Posts - [Becoming a registered user of this site](https://www.environmetrics.net.au/becoming-a-registered-user-of-this-site/): We currently support two types of registered users: 1) a contributor; and/or 2) a research associate. Contributors can post comments to our on-line Forum and leave comments elsewhere on this site. Research associates are generally persons or entities with whom … Read More - [Welcome to the new Environmetrics Australia Website!](https://www.environmetrics.net.au/hello-world/): It’s been a big effort, but it was long overdue! Our website has undergone a major facelift – the first in 10+ years! Environmetrics Australia was first registered as a company in the state of Victoria in July 2006. Although … Read More ## Pages - [booking](https://www.environmetrics.net.au/booking/) - [SSD Issues 33 & 34](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issues-33-34/): The discussion of these two SSD packages is very brief and gives only the barest indications of functionality. Indeed, the summaries provided here are essentially all they offer. It would be helpful to discuss what options exist, if any, for … Read More - [SSD Issue #38](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-38/): There is hardly a mention of censoring. This is unfortunate, as censored data, especially rightcensored observations, are common in regulatory risk assessment and there is not yet a general agreement on how, or even whether, such data should be analyzed … Read More - [SSD Issue #37](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-37/): “We strongly support model averaging as a means of (partially) resolving the omnipotent and vexing issue of distribution selection in SSD modelling.” Surely the authors mean to use the word “omnipresent.” - [SSD Issue #36](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-36/): Benchmark datasets The authors assert that it is desirable and necessary to assemble a collection reference data sets having certified properties that can be used to evaluate SSD methodologies and software tools. It is hard to argue with this and … Read More - [SSD Issue #35](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-35/): Numerical stability This is limited to a brief discussion of the Burr family of distributions. The brief criticism given is not helpful. The paper by Shao (2000) and the documentation for the original BurrliOX software already discusses the points made … Read More - [SSD Issue #34](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-34/): Discussion of SSD Toolbox software. Log-transformed data can be fit by six distributions: normal, logistic, triangular, Gumbel, Weibull, and Burr. It is also interesting that four different fitting methods are available. These are maximum likelihood, moment matching, cdf linearization, and … Read More - [SSD Issue #33](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-33/): Discussion of ssdtools software. He (sic) authors note that while it is possible to fit a single model, the emphasis in this package is on model averaging. The distributions available for this purpose are log-normal, log-logistic, and gamma by default … Read More - [SSD Issue #32](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-32/): The authors identified four options for dealing with bimodality: (i) use all data to fit the SSD using a unimodal model (i.e. do not account for bimodality); (ii) use only the data from the most sensitive species; (iii) use all … Read More - [SSD Issue #31](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-31/): The authors attempt to remove unintentional over-weighting of similar model by restricting candidate models to one for each “shape.” It is not clear that this is desirable or what “shape” means here. If models that have the same “shape”, whatever … Read More - [SSD Issue #30](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-30/): The authors advocate model averaging of HC5 estimates using AICc as weight. More specifically, they use the difference, AIC-AICmin, as weight (dropping the small c from AICc for simplicity. They note some problems when there is censoring, which is a … Read More - [SSD Issue #29](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-29/): Another potentially problematic issue with model averaging is the selection of candidate probability models. As noted by Burnham and Anderson (2002), the construction of the candidate model set involves an element of subjectivity and that “one must recognize a certain … Read More - [SSD Issue #28](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-28/): It has been suggested that model averaging is only likely to be useful when (a) the uncertainty in contributing model estimates is dominated by the conditional uncertainty of each model and not among-model uncertainty; and (b) the covariance between models … Read More - [SSD Issue #27](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-27/): As noted by Fox (2016), small samples result in low-powered goodness-of-fit tests meaning any plausible candidate model is unlikely to be rejected by these procedures. It is somewhat puzzling that the cite Chapman et al (2007) but do not note … Read More - [SSD Issue #26](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-26/): It is not clear how the ability to edit open source code enhances harmonization of approaches. It seems reasonable to think new approaches or modifications could ultimately improve the science by demonstrating improvements, but it also seems clear that, at … Read More - [SSD Issue #25](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-25/): The authors express strong opposition to the use of compiled code, such as in the recent SSD Toolbox released by USEPA. So long as the methodology and algorithms are clearly documented, their opposition to compiled code seems misguided. The use … Read More - [SSD Issue #24](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-24/): The paper also considers future directions both with and beyond the use of SSDs, with the ultimate aim of helping to facilitate greater international collaboration and, potentially, greater harmonisation of SSD methods. Given that aim, it is interesting that in … Read More - [SSD Issue #23](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-23/): Mixture data is illustrated as a general idea, but poorly illustrated in the context of SSDs and not well motivated as to relevance. - [SSD Issue #22](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-22/): The novel sections are the advocacy of model averaging and mixture models. The model averaging section should be expanded to include some noted cautions (discussed below) and more details on how the two highlighted software packages implement this. At least … Read More - [SSD Issue #21](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-21/): The list of software is interesting, but they do almost nothing with it. There is no useful discussion of what these packages do, how to use them, their effectiveness or limitations. Either develop this, put it in supplementary material, or … Read More - [SSD Issue #20](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-20/): The authors should decide what paper they want to write. The initial history of SSDs with references is good, but much too brief for a review paper and omits one important topic (censored data) and barely mentions another (Bayesian methods). - [SSD Issue #19](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-19/): To say they focused on two software packages, SSD Tool Box and ssdtools, is an overstatement. The discussion of both packages is very limited. I was expecting more. - [SSD Issue #18](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-18/): A second contribution is a discussion of model averaging applied to SSDs. The literature cited is useful. It would have been helpful to include a few detailed examples showing the utility or dangers of such an approach. It would also … Read More - [SSD Issue #17](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-17/): Example data are presented in terms of several histograms, with one exception. In the SSD depicted, the data are not illustrated, nor are they provided so the reader can try to fit a model, either the one they summarize or … Read More - [SSD Issue #16](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-16/): promote the need for models that can be used for bi- or multi-modal distributions. While this is interesting, the authors have not made a convincing case that this is a pressing need. It would have been useful if they could … Read More - [SSD Issue #15](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-15/): The language and format of the manuscript have to be carefully checked. The citations are poorly formatted, e.g. what is ENV 2019? - [SSD Issue #14](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-14/): Detailed raw data (e.g. toxicity thresholds collected for establishing SSD) and calculations are suggested to be listed. - [SSD Issue #13](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-13/): Compare the results, e.g. HC5 and quality benchmarks, derived by the new method and the traditional method, and discuss the environmental reality of the results - [SSD Issue #12](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-12/): this manuscript mainly focuses on summarizing the previous status and the recently introduced tools, the implications of the new toolbox are lack, which reduces the contribution of this manuscript on SSD evolvement - [SSD Issue #11](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-11/): the organization beginning on page 11 could use some improvement. The text gets dense and it is difficult to find the recommendations following the suggestions indicated in the first paragraph - [SSD Issue #10](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-10/): What was the log-logistic distribution selected for? - [SSD Issue #9](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-9/): The author’s state, “we have been working on adding functionality to the existing R-package ssdtools to incorporate this capability”. In what capacity are the authors working to add this functionality? - [SSD Issue #8](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-8/): it would be helpful to understand what were the limitations of the ECETOC workshop. Perhaps providing information as to who attended (e.g. affiliations, nationalities) and how many people attended- as one of the recommendations on page 28 Lines 51-54 is … Read More - [SSD Issue #7](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-7/): throughout the text the author indicate nations “developed approaches”, this should be revised to indicate what agency from a particular nation developed the approach. For example:Page 5 lines 18-20: “the Canadian province of British Columbia has developed…”Page 7 lines 19-21: … Read More - [SSD Issue #6](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-6/): Jargon and phrases like “cottage industry” , “under the hood” (line 47 pg 7) and “purpose-built software” (page 23) might not be relatable to non-North American audiences or non software experts in the field . - [SSD Issue #5](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-5/): Major findings and limitations would have been nice to see in the abstract - [SSD Issue #4](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-4/): In Figure 2 it is unclear to me exactly where in panel a the image for panel b is located? It would help if there was a black box in panel a showing exactly where panel b is a zoomed … Read More - [SSD Issue #3](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-3/): Figure 1 in particular, but to a lesser degree Figure 2 and Figure 4, have really low resolution and are difficult to read. Is it possible to provide higher resolution images? - [SSD Issue #2](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-2/): “HC” should be defined on first use and I think it would be beneficial to have a sentence explaining the reasoning for using HC5 in SSDs define= HC5 - [SSD Issue #1](https://www.environmetrics.net.au/restricted/ssd-collaboration/ssd-toc/ssd-issue-1/): an extra sentence or two in the beginning of the introduction defining/describing exactly what an SSD is would be beneficial - [Gallery](https://www.environmetrics.net.au/gallery/):     Archive David Fox receives Deming Award David Fox shown here shaking hands with the University of Wyoming President Terry Roarkreceives his award and personal check from Edwards Deming for “distinguishedperformance in his PhD studies”. Photo taken on the … Read More - [Podcasts](https://www.environmetrics.net.au/resources/podcasts/): Podcasts Drinking the piss – Prof. David Fox joins Prof. Peter Scales from the University of Melbourne to discuss desalination and recycling of treated effluent. You can either go to the University of Melbourne’s website (http://upclose.unimelb.edu.au/episode/138) or just click here … Read More - [Software](https://www.environmetrics.net.au/resources/software/): BURRLIOZ 2.0                      Click here for the program (ZIP file – 7324K) nsecR – An R package to compute a No Significant Effect Consentration in ecotoxicology                      Click here for the program (tar.gz file – 3.5K) GUMLEAF – An EXCEL … Read More - [Presentations](https://www.environmetrics.net.au/resources/presentations/): A shiny future for Burrlioz Presentation given at SETAC-AU 2021, Melbourne Australia, 30 August – 2 September 2021 (mp4 file -113MB) Bayesian Methods for Ecotoxicology Presentation given at 13th. Australasian Society for Ecotoxicology Conference, Adelaide, September 20-23 2009 (pdf file … Read More - [Documents and Reports](https://www.environmetrics.net.au/resources/documents-and-reports/): Warne MStJ, Batley GE, van Dam RA, Chapman JC, Fox DR, Hickey CW and Stauber JL. (2024). Method for deriving Australian and New Zealand water qualityguideline values for protecting aquatic ecosystems from toxicants – update of 2018 version. Prepared for … Read More - [Resources](https://www.environmetrics.net.au/resources/) - [Registration request](https://www.environmetrics.net.au/registration-request/) - [Message us](https://www.environmetrics.net.au/contact/message-us/) - [SSD Collaboration](https://www.environmetrics.net.au/restricted/ssd-collaboration/) - [Restricted](https://www.environmetrics.net.au/restricted/): Authorized Client Area - [Password Reset](https://www.environmetrics.net.au/password-reset/) - [Logout](https://www.environmetrics.net.au/logout/) - [Register](https://www.environmetrics.net.au/register/): IMPORTANT – ACCESS REQUESTS Some features/areas of this website are only available to registered users having the appropriate delegations. At present, these are: Forum contributor – allows you you write posts to our on-line forums. Research associate – This is … Read More - [Login](https://www.environmetrics.net.au/login/) - [User](https://www.environmetrics.net.au/user/) - [Member Area](https://www.environmetrics.net.au/member-area/): Members Area - [Forums](https://www.environmetrics.net.au/forums/) - [Services](https://www.environmetrics.net.au/services/): Statistical Ecotoxicology Our Principal, Professor David Fox, is a world-renowned expert in the area of statistical ecotoxicology. He has been actively researching and publishing in this domain for over 20 years and has given invited lectures, short-courses, seminars and advice … Read More - [About us](https://www.environmetrics.net.au/): We are Australia’s leading consultancy for the provision of advanced statistical services for improved environmental measurement, monitoring, and management. Our expertise covers a diverse range of fields including: ● Ecotoxicology● Spatial statistics● Advanced experimental design and analysis● Environmental risk assessment● … Read More - [Blog](https://www.environmetrics.net.au/blog/) - [Contact](https://www.environmetrics.net.au/contact/) [comment]: # (Generated by Hostinger Tools Plugin)