The Krippendorff alpha coefficient, named after the academic Klaus Krippendorff, is a statistical measure of the concordance obtained when encoding a number of units of analysis with respect to the values of a variable. Since the 1970s, Alpha has been used in content analysis, where textual units are classified by trained readers, in consulting and research, where experts code open interview data in analytical terms, in psychological tests that must be compared to alternative tests of the same phenomena, or in observational studies that record unstructured events for later analysis. The designation of a statistic as a statistic of conformity, reproducibility or reliability does not make it a valid indicator of whether coded data can be relied upon for subsequent decisions. Its mathematical structure must adapt the process of encoding units into a system of analytical terms. One-for-one coding is relatively easy to use when the analyzed content can be divided into units small enough that the units do not fit more than one category, or at least so that an evaluator can intelligently choose which unit fits best into the different categories. However, depending on the type of data, dividing the content into small units of a predefined length is not a guarantee against the production of units that are still difficult to classify into a single category. Using even smaller units, such as words, slows down manual coding tremendously. The smaller a unit of content, the more contextual units need to be used to assess the importance of the text segment. Therefore, at some point, human programmers have to return small units of content to larger segments, shut down traffic, and face the same problem. Also, for certain types of data, for example. B a photo or microblogging message such as a tweet, a unit of content appears “naturally” and cannot be “broken” into small parts without changing its holistic meaning. For example, if they coded a travel forum`s question “How much does a hotel in Nizhny Novgorod, Russia cost?”, programmers would be faced with a difficult choice between the two categories “accommodation” and “price”.
Consider a programmer who is not sure of the category in which he should classify a given coding unit.. . .