Estimating data set size for grammar extraction I have a dependency treebank including 100 sentences, which I divide into a training set and a test set. I extract some rules ((DS,PS) pairs) to convert the treebank to phrase structures. When I extract such rules from the training set, I can measure the percentage of rules (DS patterns) that cover the test set, suppose

(10, 24%), (20, 34%), (30,40%), (40,44%), (50, 55%),(60, 58%), (70, 61%)...

As you see as I increase the size of the training set, the coverage of extracted patterns increases! however its not linear!, I want to see how many data I need to reach 100% coverage?
I guess I can use a regression, but which regression? logarithmic?

Is this related to 'learning curve'? if yes how can I use regression for a learning curve?
You can never get 100% coverage for real-world grammar extraction. Grammar is complex and undefined for real-world data. In addition, it is an "open world" data problem because novel grammar phrases can always be created.

You might get 100% coverage for a small data set through overfitting.

Statistical learning theory provides a framework for predicting the limits of machine learning.