How to read Predictive model accuracy and the time frame available for the prediction

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How to read Predictive model accuracy and the time frame available for the prediction

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Hi Experts,

Need some clarification with below points.

1)How to read Predictive model accuracy: The Prediction percentage which we see after creating model is it based on individual data or group level data? How is this accuracy calculated?

2)The time frame Available for the Prediction: For user 'A' if voluntary prediction is 60% how long we can consider this like is it for month or year? When is User ' A' leaving organizations ,is it after week or month or year.

3)What’s the basis of calculating the accuracy of prediction model: To make workforce prediction we need certain types of data like performance rating, termination details, So would like to know if we are not using all the required data and still create model how much it will be helpful for us. Will it still work or it need all the required attributes data?