Gunning Fog Index is used to estimate the readability of a sentence. Is the website gunning-fog-index.com reliable for academic research purposes? If not, what software should I use?
The website clearly does not fulfill the requirements of Reproducible Research. The algorithm is not Open Source and the implementation isn't available for inspection.
There are more problems:
- The Website can go away without prior notice
- The implementation of the algorithm may change without notice
When you cannot find an Open Source implementation of the Gunning-Fox index, do it yourself. After all, the formula is not overly complex (though counting sentences and counting "complex words" can be tricky).