American Oil and Gas Reporter - April 2016 - 75
SpecialReport: Drilling Technology
Model Evaluation
One critical, but often overlooked, aspect of model selection is evaluating the
goodness-of-fit. One approach to evaluating a model fit is to generate a scatterplot of actual response values in a training
set against the predicted response using
the model. However, many models can
overfit the training data when certain
conditions are met, and in a multidimensional space, one cannot easily visualize
the prediction surface generated by the
model.
Overfitting is the result of placing too
much emphasis on reproducing the training
set. The resulting model likely contains
more degrees of freedom than are necessary to capture the underlying shape of
the curve producing the observations. In
essence, the model captures not only the
true underlying function, but also the
noise in the measurements, making it unlikely to produce good predictions.
To avoid overfitting, it is important to
move beyond using predictions on the
training data as the sole measure of model
quality. A simple solution is to use an independent test set, either a completely
new dataset (e.g., pilot data from a region
where the model is intended for use) or a
"held out" portion of the training dataset.
In either case, the model can be fit using
the training dataset, and then evaluated
with independent test observations.
Another method of model evaluation
is k-fold cross-validation. In this approach,
the training dataset is split randomly into
different k groups, or folds. Next, each
of the k groups is held out and the model
is trained on the remaining groups. That
model is used then to make predictions
on the group that was held out.
After cycling through all k groups,
there will be a single prediction for every
observation in the dataset. These crossvalidated predictions can be used to evaluate the quality of the model-fitting procedure, and can indicate whether problems
may be expected on future data collections.
It is important to note that models
trained during cross-validation are not
used for predictions; they are used only
for evaluation purposes, to provide a
better indicator on the robustness of the
single predictive model built using the
full training set.
The cross-validation procedure can be
extended by repeating the entire process
with a different random selection of k
groups. A repeated cross-validation using
multiple runs with random assignment of
the k groups will yield different predictions
on each observation. These can be averaged
to compute goodness-of-fit metrics, but
they also can give important information
about model prediction variability.
FIGURE 2
Predictive Model Results on Wolfcamp Well Dataset
APRIL 2016 75
American Oil and Gas Reporter - April 2016
Table of Contents for the Digital Edition of American Oil and Gas Reporter - April 2016
Contents
American Oil and Gas Reporter - April 2016 - Cover1
American Oil and Gas Reporter - April 2016 - Cover2
American Oil and Gas Reporter - April 2016 - 3
American Oil and Gas Reporter - April 2016 - Contents
American Oil and Gas Reporter - April 2016 - 5
American Oil and Gas Reporter - April 2016 - 6
American Oil and Gas Reporter - April 2016 - 7
American Oil and Gas Reporter - April 2016 - 8
American Oil and Gas Reporter - April 2016 - 9
American Oil and Gas Reporter - April 2016 - 10
American Oil and Gas Reporter - April 2016 - 11
American Oil and Gas Reporter - April 2016 - 12
American Oil and Gas Reporter - April 2016 - 13
American Oil and Gas Reporter - April 2016 - 14
American Oil and Gas Reporter - April 2016 - 15
American Oil and Gas Reporter - April 2016 - 16
American Oil and Gas Reporter - April 2016 - 17
American Oil and Gas Reporter - April 2016 - 18
American Oil and Gas Reporter - April 2016 - 19
American Oil and Gas Reporter - April 2016 - 20
American Oil and Gas Reporter - April 2016 - 21
American Oil and Gas Reporter - April 2016 - 22
American Oil and Gas Reporter - April 2016 - 23
American Oil and Gas Reporter - April 2016 - 24
American Oil and Gas Reporter - April 2016 - 25
American Oil and Gas Reporter - April 2016 - 26
American Oil and Gas Reporter - April 2016 - 27
American Oil and Gas Reporter - April 2016 - 28
American Oil and Gas Reporter - April 2016 - 29
American Oil and Gas Reporter - April 2016 - 30
American Oil and Gas Reporter - April 2016 - 31
American Oil and Gas Reporter - April 2016 - 32
American Oil and Gas Reporter - April 2016 - 33
American Oil and Gas Reporter - April 2016 - 34
American Oil and Gas Reporter - April 2016 - 35
American Oil and Gas Reporter - April 2016 - 36
American Oil and Gas Reporter - April 2016 - 37
American Oil and Gas Reporter - April 2016 - 38
American Oil and Gas Reporter - April 2016 - 39
American Oil and Gas Reporter - April 2016 - 40
American Oil and Gas Reporter - April 2016 - 41
American Oil and Gas Reporter - April 2016 - 42
American Oil and Gas Reporter - April 2016 - 43
American Oil and Gas Reporter - April 2016 - 44
American Oil and Gas Reporter - April 2016 - 45
American Oil and Gas Reporter - April 2016 - 46
American Oil and Gas Reporter - April 2016 - 47
American Oil and Gas Reporter - April 2016 - 48
American Oil and Gas Reporter - April 2016 - 49
American Oil and Gas Reporter - April 2016 - 50
American Oil and Gas Reporter - April 2016 - 51
American Oil and Gas Reporter - April 2016 - 52
American Oil and Gas Reporter - April 2016 - 53
American Oil and Gas Reporter - April 2016 - 54
American Oil and Gas Reporter - April 2016 - 55
American Oil and Gas Reporter - April 2016 - 56
American Oil and Gas Reporter - April 2016 - 57
American Oil and Gas Reporter - April 2016 - 58
American Oil and Gas Reporter - April 2016 - 59
American Oil and Gas Reporter - April 2016 - 60
American Oil and Gas Reporter - April 2016 - 61
American Oil and Gas Reporter - April 2016 - 62
American Oil and Gas Reporter - April 2016 - 63
American Oil and Gas Reporter - April 2016 - 64
American Oil and Gas Reporter - April 2016 - 65
American Oil and Gas Reporter - April 2016 - 66
American Oil and Gas Reporter - April 2016 - 67
American Oil and Gas Reporter - April 2016 - 68
American Oil and Gas Reporter - April 2016 - 69
American Oil and Gas Reporter - April 2016 - 70
American Oil and Gas Reporter - April 2016 - 71
American Oil and Gas Reporter - April 2016 - 72
American Oil and Gas Reporter - April 2016 - 73
American Oil and Gas Reporter - April 2016 - 74
American Oil and Gas Reporter - April 2016 - 75
American Oil and Gas Reporter - April 2016 - 76
American Oil and Gas Reporter - April 2016 - 77
American Oil and Gas Reporter - April 2016 - 78
American Oil and Gas Reporter - April 2016 - 79
American Oil and Gas Reporter - April 2016 - 80
American Oil and Gas Reporter - April 2016 - 81
American Oil and Gas Reporter - April 2016 - 82
American Oil and Gas Reporter - April 2016 - 83
American Oil and Gas Reporter - April 2016 - 84
American Oil and Gas Reporter - April 2016 - 85
American Oil and Gas Reporter - April 2016 - 86
American Oil and Gas Reporter - April 2016 - 87
American Oil and Gas Reporter - April 2016 - 88
American Oil and Gas Reporter - April 2016 - 89
American Oil and Gas Reporter - April 2016 - 90
American Oil and Gas Reporter - April 2016 - 91
American Oil and Gas Reporter - April 2016 - 92
American Oil and Gas Reporter - April 2016 - 93
American Oil and Gas Reporter - April 2016 - 94
American Oil and Gas Reporter - April 2016 - 95
American Oil and Gas Reporter - April 2016 - 96
American Oil and Gas Reporter - April 2016 - 97
American Oil and Gas Reporter - April 2016 - 98
American Oil and Gas Reporter - April 2016 - 99
American Oil and Gas Reporter - April 2016 - 100
American Oil and Gas Reporter - April 2016 - 101
American Oil and Gas Reporter - April 2016 - 102
American Oil and Gas Reporter - April 2016 - 103
American Oil and Gas Reporter - April 2016 - 104
American Oil and Gas Reporter - April 2016 - 105
American Oil and Gas Reporter - April 2016 - 106
American Oil and Gas Reporter - April 2016 - 107
American Oil and Gas Reporter - April 2016 - 108
American Oil and Gas Reporter - April 2016 - 109
American Oil and Gas Reporter - April 2016 - 110
American Oil and Gas Reporter - April 2016 - 111
American Oil and Gas Reporter - April 2016 - 112
American Oil and Gas Reporter - April 2016 - 113
American Oil and Gas Reporter - April 2016 - 114
American Oil and Gas Reporter - April 2016 - 115
American Oil and Gas Reporter - April 2016 - 116
American Oil and Gas Reporter - April 2016 - 117
American Oil and Gas Reporter - April 2016 - 118
American Oil and Gas Reporter - April 2016 - 119
American Oil and Gas Reporter - April 2016 - 120
American Oil and Gas Reporter - April 2016 - 121
American Oil and Gas Reporter - April 2016 - 122
American Oil and Gas Reporter - April 2016 - 123
American Oil and Gas Reporter - April 2016 - 124
American Oil and Gas Reporter - April 2016 - 125
American Oil and Gas Reporter - April 2016 - 126
American Oil and Gas Reporter - April 2016 - 127
American Oil and Gas Reporter - April 2016 - 128
American Oil and Gas Reporter - April 2016 - 129
American Oil and Gas Reporter - April 2016 - 130
American Oil and Gas Reporter - April 2016 - Cover3
American Oil and Gas Reporter - April 2016 - Cover4
https://www.nxtbook.com/nxtbooks/aogr/202404
https://www.nxtbook.com/nxtbooks/aogr/202403
https://www.nxtbook.com/nxtbooks/aogr/202402
https://www.nxtbook.com/nxtbooks/aogr/202401
https://www.nxtbook.com/nxtbooks/aogr/202312
https://www.nxtbook.com/nxtbooks/aogr/202311
https://www.nxtbook.com/nxtbooks/aogr/pbios_202310
https://www.nxtbook.com/nxtbooks/aogr/202309
https://www.nxtbook.com/nxtbooks/aogr/202308
https://www.nxtbook.com/nxtbooks/aogr/202307
https://www.nxtbook.com/nxtbooks/aogr/202306
https://www.nxtbook.com/nxtbooks/aogr/202305
https://www.nxtbook.com/nxtbooks/aogr/202304
https://www.nxtbook.com/nxtbooks/aogr/202303
https://www.nxtbook.com/nxtbooks/aogr/202302
https://www.nxtbook.com/nxtbooks/aogr/202301
https://www.nxtbook.com/nxtbooks/aogr/202212
https://www.nxtbook.com/nxtbooks/aogr/202211
https://www.nxtbook.com/nxtbooks/aogr/202210
https://www.nxtbook.com/nxtbooks/aogr/202209
https://www.nxtbook.com/nxtbooks/aogr/202208
https://www.nxtbook.com/nxtbooks/aogr/202207
https://www.nxtbook.com/nxtbooks/aogr/202206
https://www.nxtbook.com/nxtbooks/aogr/202205
https://www.nxtbook.com/nxtbooks/aogr/202204
https://www.nxtbook.com/nxtbooks/aogr/202203
https://www.nxtbook.com/nxtbooks/aogr/202202
https://www.nxtbook.com/nxtbooks/aogr/202201
https://www.nxtbook.com/nxtbooks/aogr/202112
https://www.nxtbook.com/nxtbooks/aogr/202111
https://www.nxtbook.com/nxtbooks/aogr/pbios_202110
https://www.nxtbook.com/nxtbooks/aogr/202109
https://www.nxtbook.com/nxtbooks/aogr/202108
https://www.nxtbook.com/nxtbooks/aogr/202107
https://www.nxtbook.com/nxtbooks/aogr/202106
https://www.nxtbook.com/nxtbooks/aogr/202105
https://www.nxtbook.com/nxtbooks/aogr/202104
https://www.nxtbook.com/nxtbooks/aogr/202103
https://www.nxtbook.com/nxtbooks/aogr/202102
https://www.nxtbook.com/nxtbooks/aogr/202101
https://www.nxtbook.com/nxtbooks/aogr/202012
https://www.nxtbook.com/nxtbooks/aogr/202011
https://www.nxtbook.com/nxtbooks/aogr/202010
https://www.nxtbook.com/nxtbooks/aogr/202009
https://www.nxtbook.com/nxtbooks/aogr/202008
https://www.nxtbook.com/nxtbooks/aogr/202007
https://www.nxtbook.com/nxtbooks/aogr/202006
https://www.nxtbook.com/nxtbooks/aogr/202005
https://www.nxtbook.com/nxtbooks/aogr/202004
https://www.nxtbook.com/nxtbooks/aogr/202003
https://www.nxtbook.com/nxtbooks/aogr/202002
https://www.nxtbook.com/nxtbooks/aogr/202001
https://www.nxtbook.com/nxtbooks/aogr/201912
https://www.nxtbook.com/nxtbooks/aogr/201911
https://www.nxtbook.com/nxtbooks/aogr/201910
https://www.nxtbook.com/nxtbooks/aogr/201909
https://www.nxtbook.com/nxtbooks/aogr/201908
https://www.nxtbook.com/nxtbooks/aogr/201907
https://www.nxtbook.com/nxtbooks/aogr/201906
https://www.nxtbook.com/nxtbooks/aogr/201905
https://www.nxtbook.com/nxtbooks/aogr/201904
https://www.nxtbook.com/nxtbooks/aogr/201903
https://www.nxtbook.com/nxtbooks/aogr/201902
https://www.nxtbook.com/nxtbooks/aogr/201901
https://www.nxtbook.com/nxtbooks/aogr/201812
https://www.nxtbook.com/nxtbooks/aogr/201811
https://www.nxtbook.com/nxtbooks/aogr/201810
https://www.nxtbook.com/nxtbooks/aogr/pbios_201810
https://www.nxtbook.com/nxtbooks/aogr/201809
https://www.nxtbook.com/nxtbooks/aogr/201808
https://www.nxtbook.com/nxtbooks/aogr/201807
https://www.nxtbook.com/nxtbooks/aogr/201806
https://www.nxtbook.com/nxtbooks/aogr/201805
https://www.nxtbook.com/nxtbooks/aogr/201804
https://www.nxtbook.com/nxtbooks/aogr/201803
https://www.nxtbook.com/nxtbooks/aogr/201802
https://www.nxtbook.com/nxtbooks/aogr/201801
https://www.nxtbook.com/nxtbooks/aogr/201712
https://www.nxtbook.com/nxtbooks/aogr/201711
https://www.nxtbook.com/nxtbooks/aogr/201710
https://www.nxtbook.com/nxtbooks/aogr/201709
https://www.nxtbook.com/nxtbooks/aogr/201708
https://www.nxtbook.com/nxtbooks/aogr/201707
https://www.nxtbook.com/nxtbooks/aogr/201706
https://www.nxtbook.com/nxtbooks/aogr/201705
https://www.nxtbook.com/nxtbooks/aogr/201704
https://www.nxtbook.com/nxtbooks/aogr/201703
https://www.nxtbook.com/nxtbooks/aogr/201702
https://www.nxtbook.com/nxtbooks/aogr/201701
https://www.nxtbook.com/nxtbooks/aogr/201612
https://www.nxtbook.com/nxtbooks/aogr/201611
https://www.nxtbook.com/nxtbooks/aogr/201610
https://www.nxtbook.com/nxtbooks/aogr/pbios2016_programguide
https://www.nxtbook.com/nxtbooks/aogr/201609
https://www.nxtbook.com/nxtbooks/aogr/201608
https://www.nxtbook.com/nxtbooks/aogr/201607
https://www.nxtbook.com/nxtbooks/aogr/201606
https://www.nxtbook.com/nxtbooks/aogr/201605
https://www.nxtbook.com/nxtbooks/aogr/201604
https://www.nxtbook.com/nxtbooks/aogr/201603
https://www.nxtbook.com/nxtbooks/aogr/201602
https://www.nxtbook.com/nxtbooks/aogr/201601
https://www.nxtbook.com/nxtbooks/aogr/201512
https://www.nxtbook.com/nxtbooks/aogr/201511
https://www.nxtbook.com/nxtbooks/aogr/201510
https://www.nxtbook.com/nxtbooks/aogr/201509
https://www.nxtbook.com/nxtbooks/aogr/201508
https://www.nxtbook.com/nxtbooks/aogr/201507
https://www.nxtbook.com/nxtbooks/aogr/201506
https://www.nxtbook.com/nxtbooks/aogr/201505
https://www.nxtbook.com/nxtbooks/aogr/201504
https://www.nxtbook.com/nxtbooks/aogr/201503
https://www.nxtbook.com/nxtbooks/aogr/201502
https://www.nxtbook.com/nxtbooks/aogr/201501
https://www.nxtbook.com/nxtbooks/aogr/201412
https://www.nxtbook.com/nxtbooks/aogr/201411
https://www.nxtbook.com/nxtbooks/aogr/201410
https://www.nxtbook.com/nxtbooks/aogr/201409
https://www.nxtbook.com/nxtbooks/aogr/pbios2014_programguide
https://www.nxtbook.com/nxtbooks/aogr/201408
https://www.nxtbook.com/nxtbooks/aogr/201407
https://www.nxtbook.com/nxtbooks/aogr/201406
https://www.nxtbook.com/nxtbooks/aogr/201405
https://www.nxtbook.com/nxtbooks/aogr/201404
https://www.nxtbook.com/nxtbooks/aogr/201403
https://www.nxtbook.com/nxtbooks/aogr/201402
https://www.nxtbook.com/nxtbooks/aogr/201401
https://www.nxtbook.com/nxtbooks/aogr/201312
https://www.nxtbook.com/nxtbooks/aogr/201311
https://www.nxtbook.com/nxtbooks/aogr/201310
https://www.nxtbook.com/nxtbooks/aogr/201309
https://www.nxtbook.com/nxtbooks/aogr/201308
https://www.nxtbook.com/nxtbooks/aogr/201307
https://www.nxtbook.com/nxtbooks/aogr/201306
https://www.nxtbook.com/nxtbooks/aogr/201305
https://www.nxtbook.com/nxtbooks/aogr/201304
https://www.nxtbook.com/nxtbooks/aogr/201303
https://www.nxtbook.com/nxtbooks/aogr/201302
https://www.nxtbook.com/nxtbooks/aogr/201301
https://www.nxtbook.com/nxtbooks/aogr/201212
https://www.nxtbook.com/nxtbooks/aogr/201211
https://www.nxtbook.com/nxtbooks/aogr/201210
https://www.nxtbook.com/nxtbooks/aogr/201209
https://www.nxtbook.com/nxtbooks/aogr/2012_pbios
https://www.nxtbook.com/nxtbooks/aogr/201208
https://www.nxtbook.com/nxtbooks/aogr/201207
https://www.nxtbook.com/nxtbooks/aogr/201206
https://www.nxtbook.com/nxtbooks/aogr/201205
https://www.nxtbook.com/nxtbooks/aogr/201204
https://www.nxtbook.com/nxtbooks/aogr/201203
https://www.nxtbook.com/nxtbooks/aogr/201202
https://www.nxtbook.com/nxtbooks/aogr/201201
https://www.nxtbook.com/nxtbooks/demo/aogr_clone
https://www.nxtbook.com/nxtbooks/aogr/201112
https://www.nxtbookmedia.com