Terminology

Activity
In general, an activity is something that someone does. For example, 'hiking' in the course of a hiking day in school, 'experiencing a video', 'attempting a test', 'carrying out an experiment', or 'participating in a course'. Within the xolp system, these processes (activities) are considered to be referred to/identified by IRIs.
Note: The detailed semantics of how to represent activities (processes) and/or their instances is up to the context and domain of the client of the xolp package. In other words, whether or not the fact that "three people answered a personalized questionnaire" translates into one activity (performed by three people) or into three distinct activities) has to be decided by the client package's designer.
Indicator
An indicator is a small-grained a measurable fact, such as the amount of points scored by answering a question, or the fact that a user has downloaded a PDF file. Each indicator is associated with exactly one activity.
Competency
A competency is a demand-oriented human potentiality for action that can be learned and involves cognitive and non-cognitive elements (see Stahl and Wild 2006).
Evaluation Schema
An evaluation schema is a schema for translating learning indicators into semantically more meaningful units (such as grades). Each evaluation schema has (at least two) ordered levels (e.g. "not attempted" and "attempted"), one or more of which are considered. For example, the Austrian grading schema, which comprises five distinct grades (1 to 5) is an evaluation schema with five levels.
Evaluation Scale
An evaluation scale specifies the ranges of the levels of an evaluation schema in terms of percentage thresholds. For example, in the context of activity A, one might need at least 90% to gain the highest level, whereas for activity B 75% are considered sufficient.

Figure 1: Evaluation Schemas and Evaluation Scales exemplified.