Masquerading factors

A true factor exerts its effect directly on the system and is correctly identified as doing so. A masquerading factor also exerts its effect directly on the system but is incorrectly assigned some other identity. 

But time is not the true factor sugar content of the fruit is the true factor, and it is masquerading as time. The masquerade is successful because of the high correlation between time of year and sugar content. 

A slightly different type of masquerade takes place when a single, unknown factor influences two outputs, and one of the outputs is mistaken as a factor. G. E. P. Box has given such masquerading factors the more dramatic names of either latent variables or lurking variables [Box, Hunter, and Hunter (1978), and Joiner (1981)]. 

Figure 1.8 Alternative view of a wine-malcing process suggesting sugar content as a masquerading factor.

Think for a moment why it is possible for factors to masquerade as other variables. Why are we sometimes fooled about the true identity of a factor Why was time of year said to be a factor in the dryness of wine Why was foaming thought to be a factor in the alcohol content of wine ... 

Occasionally, a response from a system will act as a true factor to the same system, a phenomenon that is generally referred to as feedback. (This is not the same as the situation of masquerading factors.) Feedback is often classified as positive if it enhances the response being returned as a factor, or negative if it diminishes the response. 

The discrete factor solvent number is recognized as a simple bookkeeping designation. We can replace it with the continuous factor dipole moment expressed on a ratio scale and obtain, finally, the response surface shown in Figure 2.13. A special note of caution is in order. Even when data such as that shown in Figure 2.13 is obtained, the suspected property might not be responsible for the observed effect it may well be that a different, correlated property is the true cause (see Section 1.2 on masquerading factors). 

Wilson (1952), Huff (1954), Campbell (1974), Moore (1979)] a single experiment is not sufficient to identify which of any number of controlled or uncontrolled factors might be responsible for the measured response (see Section 1.2 on masquerading factors). In the case of Beer s Law, for example, the observed absorbance might be caused not by the supposed chemical species but rather by some unknown impurity in the solvent. 

Based on this information, the researcher would probably conclude that the concentration of sodium ion does have an effect on the rate of the enzyme catalyzed reaction. However, this conclusion might be wrong because of the lurking presence of a highly correlated, masquerading factor, time (see Section 1.2). 

Confidence intervals (Equation 10.66) suggest that it is unlikely the sodium ion concentration has a statistically significant effect upon the rate of the enzyme catalyzed reaction some other factor, one that is correlated with time, is probably responsible for the observed effect (see Section 1.2 on masquerading factors). 

Hathout EH, Cockburn BN, Mace JW, Sharkey J, Chen-Daniel J, Bell GI. A case of hepatocyte nuclear factor-1 alpha diabetes/MODY3 masquerading as type 1 diabetes in a Mexican-American adolescent and responsive to a low dose of sulfonylurea. Diabetes Care 1999 22(5) 867-8. 

This last consideration from the Wands factors directly assesses the amount of experimentation required to make or use the invention in view of the direction provided in the disclosure. At first blush, this might appear to be the final determination masquerading as the eighth factor, but it s not. The ultimate determination of whether the invention is enabled or not is not whether significant experimentation is required but whether the experimentation required to make and use the invention is an unreasonable or undue amount. Some experimentation may still be required after reading the disclosure but it is not per se unreasonable if the experimentation is routine or if the disclosure provides considerable guidance as to the direction the experimentation should proceed. 

Wagner TE, Huseby ES, Huseby JS. Exacerbation of Mycobacterium tuberculosis enteritis masquerading as Crohn s disease after treatment with a tumor necrosis factor-alpha inhibitor. Am J Med 2002 112(l) 67-9. 

Some factors may masquerade as depression, be co-morbid, or make depression harder to treat. 

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