What is validation

Theoretical appropriateness of a model has to do with the choice of the model. Is a latent variable structure expected on theoretical grounds Is this structure bilinear or trilinear in nature Are offsets expected Are linearizing transformations or preprocessing needed etc. 

Computational correctness is mainly concerned with whether the algorithm has converged to the desired global minimum or to unintended local minima and explaining why this has happened. Also rounding-off error is important, as is reproducibility of the calculations. These are algorithmic problems. For a data analyst such aspects should ideally not be of concern, but unfortunately, some three-way models are not numerically simple to fit. 

Multi-way Analysis With Applications in the Chemical Sciences. A. Smilde, R. Bro and R Geladi 2004 John Wiley Sons, Ltd ISBN 0-471-98691-7 

Multi-way Analysis With Applications in the Chemical Sciences 

Statistical reliability is related to appropriateness of distributional assumptions, the stability of solutions to resampling, choice of dimensionality and confidence intervals of the model parameters. The statistical reliability is often difficult to quantify in practical data analysis, e.g., because of small sample sets or poor distributional knowledge of the system. 

---

Together with the fast development of analytical methodologies, great importance is nowadays attached to the quality of the measurement data. Besides the necessary reporting of any result with its MU and traceability of the results to stated standards or references (Section 8.2.2), a third crucial aspect of analytical methods of whichever type is their status of validation. It is internationally recognized that validation is necessary in analytical laboratories. However, less is known about what is validation and what should be validated, why validation is important, when and by whom validation is performed, and finally, how it is carried out practically. This Chapter has tried to answer these questions. 

Not only has the Internet offered an explosion in information and access to it, it has linked people through new devices in new ways. For nearly a century, the telephone linked places. You called a business or home. Today, cell phones and other devices fink individuals wherever they are. The links offer voice, text, photos, applications, and data in ways never possible. Concurrently, a challenge for everyone is differentiating quality information from misinformation in nearly every field, including safety and health. Individuals must decide what is valid and reliable information. 

This Section considers one of the more important dilemmas in moleculai physics Given a Bom-Oppenheimer-Huang system, what is the minimal sub-Hilbert space for which diabatization is still valid. 

This situation, despite the fact that reliability is increasing, is very undesirable. A considerable effort will be needed to revise the shape of the potential functions such that transferability is greatly enhanced and the number of atom types can be reduced. After all, there is only one type of carbon it has mass 12 and charge 6 and that is all that matters. What is obviously most needed is to incorporate essential many-body interactions in a proper way. In all present non-polarisable force fields many-body interactions are incorporated in an average way into pair-additive terms. In general, errors in one term are compensated by parameter adjustments in other terms, and the resulting force field is only valid for a limited range of environments. 

When we compare industrial air technology (lAT) with comfort ventilation, we can see that technologically our task is very challenging. To fulfill all the needs of the end user is often impossible. If the lAQ is fulfilled, the amount of air may be so large that draftiness is too high. We must also have the courage to say what is possible and what is not. We also have to cteate tools to validate this. 

Productivity is a measure of productive efficiency calculated as the ratio of what is produced to what is required to produce it. Productivity can therefore be considered as a characteristic of a process, and therefore a measure of the quality of a process. Consider two process each producing the same product but one delivers the result using less resources and hence as a consequence has a higher productivity. The process with the higher productivity could thus be regarded as being of better quality. However, measuring resource consumption alone would not be a valid means of comparison as inputs could be vastly different. Hence productivity is a quality characteristic. 

As SR decreases, 1 must be decreased too (and thereby also the inlet pressure loss/total pressure ratio is decreased). This is what is really observed when dispersed fillers are added to polymer [182,190,193,194], The rubber phase in heat resistant polystyrene behaves much like a dispersed filler it also diminishes the inlet correction [195]. For polystyrene with different fillers the following relationship was found to be valid [196] ... 

The Monod rate model is valid for a CSTR bioreactor with maximum specific growth rate of 0.5 li 1 and K, 2 g-1. What would be a suitable dilution rate at steady-state condition, where there is no cell death if initial substrate concentration is 50g-l-1 and yield of biomass on substrate is 100%. 

The basis for assessment of river quality is valid data, but the question of data validity is secondary to the fundamental question What is the purpose of the river quality assessment activity What questions are being asked In short the means are determined by the ends. If, for example, the intent of an assessment program is to ascertain compliance with law, then a fixed interval "grab sampling program could be established at various river system sites selected on the basis of established guidelines which are consistent with the... 

What is needed is an alternative approach which permits development of valid cause and effect relationships. This strategy, one involving intensive surveys, is referred to here as mechanistic. The Willamette River, Oregon, USA, is used as a case study to illustrate quantitative, semi-quantitative and qualitative approaches to mechanistic assessment of river water quality using, respectively, dissolved oxygen depletion, erosion/deposition and potentially toxic trace elements as examples. 

The simplified theory allows the time-dependent wave function to be calculated rapidly for any specified laser field. However, controlling the dynamics of the charge carriers requires the answer to an inverse question [18-22]. That is, given a specific target or objective, what is the laser field that best drives the system to that objective Several methods have been developed to address this question. This section sketches one method, valid in the weak response (perturbative) regime in which most experiments on semiconductors are performed. 

The whole analysis given hitherto has been conditioned by the strict validity of the Arrhenius equation. In fact, this equation is satisfactory for most organic work (191, 230), or for solution reactions in general, the main reason being the limited temperature range available in solution and a relatively low accuracy with complex reactions. What is still more important, the accuracy of the Arrhenius equation is usually completely sufficient when compared with the low... 

What is certain is that elastomers can and do perform critical duties in engineering apphcations which function for many years in conditions that can be severe or hostile. The basic requirement is to select the right elastomer for the job—which in turn can mean to carry out the most appropriate design, test, and validation work before putting a component into service. 

An eye should also be kept on the absolute size of the standard deviation before and after a proposed elimination. If the elimination of a questionable point results in a standard deviation that is markedly smaller than what is common experience for the test at hand, the P-test cannot be used for confirmation, unless S2 is replaced by either the method obtained during the validation, or its lower confidence limit. 

What is available to find out the conditions ensuring the validity of formula (7) is the function... 

The validity of pharmacoeconomic data is invariably diminished by two important factors a failure to account for all direct and indirect cost outcomes, and the difficulty of assigning costs to human experiences. In schizophrenia, validity is further reduced by the near-impossibility of conducting trials over several years, or even decades, so as to approach the reality of what is usually a lifelong illness. Given these observations, it would be imprudent to act on the minutiae of data generated in even the best-conducted trials, but it may well be appropriate to draw broad conclusions. 

---