3G Watchdog Pro usage prediction capability is one of its most useful features. It is important for the user not only to know her/his current consumption, but also to anticipate its usage by the end of the current plan period or day so she/he can take corrective action if necessary.
However usage prediction is not an exact science, and there is no way to predict usage with 100% accuracy. Different strategies may be implemented, and as of version 1.22.0, 3G Watchdog offers the choice between 3 prediction methods:
- Standard (aka “Amnesic”) method: this prediction is based on usage since the beginning of the current period (day or plan), and is a simple linear extrapolation of this usage. Usage history before the beginning of the current period is not taken into account (hence the nickname “amnesic”). A drawback of this method is that the prediction is unavailable at the beginning of each period until enough usage data can be collected to get a significant prediction. Even after enough data has eventually been collected to supply a prediction, this prediction strategy still tends to amplify your usage in the initial part of the period: for example if you had exceptionally high consumption in the first hour, the prediction will be very high too, which can be disturbing. Nevertherless the prediction will become more smoothed and accurate as time passes.
- Moving average [since 1.22.0]: this prediction is based on the average usage from the last N days (N configurable, default: 30). This strategy tends to smooth the prediction because past usage (before the current period) is taken into account. It works well on a large period such as a monthly plan, but may produce strange results with current day prediction, as the importance given to past usage may outweight the actual usage for the day.
- Mixed [since 1.22.0]: this prediction is based on a dynamically weighted combination of the two above methods. More weight is given to the moving average prediction (based on past usage) at the beginning of the period (reflecting the absence of actual data), but as time passes and more actual usage data becomes available the balance shifts towards the amnesic prediction (reflecting the fact that actual data is more important than speculative one).
No method is perfect. You might want to experiment in order to find which one best matches your usage pattern. You can freely switch from one method to the other. Go to 3GW Settings > Prediction to select the prediction method.