For both malformations, the policy category of reference for pregnancy termination was no legal gestational age limit.
For Down's syndrome, the policy category of reference for prenatal screening was first or second-trimester screening for the whole country; for NTD, the policy category of reference was having a national policy in place for routine ultrasound.
A third category of reference books for language lovers is usage — advice to the grammarlorn, pioneered by Henry Fowler with his "Modern English Usage" and updated generations later by Robert Burchfield.
The wider culture began to make reference to a category of Christians called progressive.
Users should be aware that (unlike in methods such as penalised likelihood) different parameterisations for example, different choices of reference category for a categorical variable can give somewhat different answers.
The same method is used whether the predictor is quantitative or a dummy for a categorical variable; it is therefore not exactly invariant to the choice of reference category for categorical variables with more than 2 levels.
The RRR is interpreted as the relative risk of one outcome in relation to the reference category for a specified category of an independent variable compared with the reference.
The reference category of HIV status for egos and alters was "HIV-negative".
Higher PACIC scores (0.22) were associated with patients who had been visiting their practice for less than two years compared with the reference category of visiting a practice for more than seven years (p = 0.001).
The HR associated with an indicator variable for a category represented the risk for participants with that variable compared with the risk of participants in the reference category.
The category of object, for example, is distinguished by reference to the linguistic category of proper name (Dummett 1973/1981, 55 56; cf. Wright 1983, 13 and Hale 1987, 3 4)—i.e., an object just is the correlate of a proper name, where proper names are held to include all singular terms (including singular substantival phrases preceded by the definite article).
