A search result that displays an N/A instead of a 1 to 5 score indicates that netTrekker was unable to calculate a readability score for that learning resource.
Failure to calculate scores can result for a variety of reasons including:
- Learning resource content is not in a suitable format (e.g. Flash or PDF)
- Invalid file extensions
- Too little text to measure for readability
- File-processing errors that impede reliable readability analysis