A number of issues surround corrections for sampling errors.
Our approach simultaneously eliminates RNA quality control issues for samples run in parallel while improving efficiency in the use of time and materials.
The design should incorporate appropriate control procedures for collecting and processing specimens, validated analytical methods, and statistical analyses that account for sampling issues such as urine dilution (Barr et al. 2005) and collection times (Calafat and Needham 2009).
Monomer and oligomer desorption was minimized by imaging directly after adsorption; a loss of small aggregates species would likely be an issue for samples stored under a buffer at RT for a significant period of time.
Problems with reproducibility of results associated with storage conditions and transportation of blood samples from distant sources have been reported (Scott et al, 1999), although reproducibility has been shown not to be an issue for samples transported over short distances (Roberts et al, 1999; Smart et al, 2003).
Application of food web analysis in risk assessments demands consideration of: 1) different kinds of food webs; 2) definition of trophic guilds; 3) variation in food webs with habitat, space, and time; and 4) issues for basic sampling design and collection of dietary data.
For design issues, sampling and generalizabilty as well as randomized and quasi-experimental designs for causal inference are discussed.
Although these studies were classified as of high methodological quality by Jadad's score, other quality issues (for example, sample size, duration of follow-up and retention rates) were not considered and may limit the strength of these results.
Finally, the IRB approval process included completing an online application detailing the study, including such information as research purpose, methods, locations, researchers' background, data confidentiality issues, justification for sample sizes, and justification for conducing research on populations that are considered vulnerable (e.g., K 12 students).
A second issue is sampling variability (problematic for standard error calculations when data are treated as fixed rather than random variables).
