I’m beginning to write the second edition of Nondetects And Data Analysis, lovingly known as NADA. I’d like to get your ideas on what should be added, changed, or deleted from the current book. Here’s my plans:
1. a new chapter on multivariate methods with nondetects. How to do principal components, cluster analysis, etc. when some data are nondetects.
2. a new chapter on R. More detail on the NADA for R package and how to do all these methods, without the annoyance of ‘flipping’ data now required by commercial software, within the free, internationally-standard R statistical package.
3. more detail on both parametric and nonparametric methods when coding values truly below the detection limit differently from values lying between the detection and quantitation limits.
4. a new introduction along the lines of my paper “Fabricating Data” doi:10.1016/j.chemosphere.2006.04.051    
5. a section on how to sum a series of values, some of which are nondetects. The primary application is to things like dioxin congeners, TECs, TEQs, etc. This information is in my paper “Summing Nondetects”, currently accepted for publication in the journal Integrated Environmental Assessment and Management (SETAC).

Or email me using the Contact Us tab.

-- Dennis Helsel