The evaluation metric for this competition is Root Mean Square Error. Root Mean Square Error (RMSE) is commonly used in regression analysis and forecasting, and measures the standard deviation of the residuals arising between predicted and actual observed values for a modelling process.

##Submission Format
For every author in the dataset, submission files should contain two columns: userID and rating. 'rating' is the predicted rating for a given user-movie pair.
The file should contain a header and have the following format:

```
userID,rating
1,1.0
2,2.0
3,3.0
```