ran the ALS model for implicit feedback thing. Then I used the .transform method of the model to predict the ratings for the original dataset. My dataset is of the form (user,item,rating)

I see something like below:


Why is the last prediction value negative ?. Isn't the transform method giving the prediction(probability) of seeing the rating as 1?. I had counts data for rating (implicit feedback) and for validation dataset I binarized the rating (1 if >0 else 0). My training data has rating positive (it's basically the count of views to a video). 

I used following to train: 

 als = ALS(rank=x, maxIter=15, regParam=y, implicitPrefs=True,alpha=40.0)


What does negative prediction mean here and is it ok to have that?