Latin Phrases in Empirical Research
Latin, the former official language of science from previous centuries, lingers in today’s scientific community as a throwback to the earlier days of modern science. Throughout the last few centuries, Latin has been associated with the learned, universities, and the church. Even today, Latin still carries with it an air of sophistication and refinement.
The Latin phrase “a priori" is so prevalent in the English that it even appears in its unaltered form in most dictionaries. An appropriate literal translation is “from the former" and is used when a researcher has specified relationships among variables – or hypotheses – without the benefit of data. By specifying hypotheses a priori, the researcher has increased the validity of the relationships because he/she has reduced the chances that the relationships are specific to one sample of data rather than generalizable to other samples or populations.
The Latin phrase “a posteriori", also found in an English dictionary, can be appropriately translated as “from the latter." This phrase is used to indicate that hypotheses are the result of observation or data from which the relationships were derived. Although the external validity of such hypotheses are much lower than in an a priori specification, a posteriori methods do allow for the discovery of relationships that would have been difficult, if not impossible, to predict without the benefit of data.
Often, the phrase “ad hoc" is used when a posteriori is more appropriate. Ad hoc, translated literally as “for this [purpose]", is used when a researcher wants to convey that findings resulted from the benefit of data. Although similar to a posteriori, ad hoc analysis help explain failed support for a priori hypotheses, not as the main method driving the research. Ad hoc analysis are often exploratory in nature and are used to push knowledge forward in an otherwise a priori study to point future research in a new directions, explain phenomena that could not be explained by the a priori method, or explore unconventional relationships not warranted by a priori specification.