A person’s ability to communicate in a foreign or second language has four elements: Accuracy (grammatical correctness), sociolinguistics (context of the language to the world around them), discourse (ability to authoritatively about a topic) and strategic competence (ability to get your meaning across to another person). The most commonly assessed of these areas would be accuracy (grammar) which can be assessed through the four skills of reading, writing, listening and speaking.
Grammatical competence itself has three components: Form and syntax (how the words are made and how they are strung together), meaning (the message the grammar is intended to give), and pragmatism (implied meaning). Assessment is typically done through such tests as sentence unscrambling, fill-in-the-blanks, error detection, sentence completion, picture description, elicited imitation, judging grammatical correctness in student's written work (probably the best way), and cloze passages (Larsen-Freeman, 2009). However, these kinds of tests do not get to whether students can actually use grammar in real-life situations. That’s where the communicative approach comes in by assessing through the creation of texts and face to face listening and speaking time. When a teacher interviews or listens to a student they can use scales to measure accuracy and complexity but these are judgment calls on the part of the teacher so the possibility of inconsistency is higher (McNamara and Roever, 2006).