Targeted Marketing, KDD Cup and Customer Modeling

Transcription

1 Targeted Marketing, KDD Cup and Customer Modeling

2 Outline Direct Marketing Review: Evaluation: Lift, Gains KDD Cup 1997 Lift and Benefit estimation Privacy and Data Mining 2

3 Direct Marketing Paradigm Find most likely prospects to contact Not everybody needs to be contacted Number of targets is usually much smaller than number of prospects Typical Applications retailers, catalogues, direct mail (and ) customer acquisition, cross-sell, attrition... 3

4 Direct Marketing Evaluation Accuracy on the entire dataset is not the right measure Approach develop a target model score all prospects and rank them by decreasing score select top P% of prospects for action Evaluate Performance on top P% using Gains and Lift 4

5 CPH (Gains): Random List vs Model-ranked list Cumulative % Hits % of random list have 5% of targets, but 5% of model ranked list have 21% of targets CPH(5%,model)=21%. Random Model Pct list

6 Lift Curve Lift(P) = CPH(P) / P Lift (at 5%) = 21% / 5% = 4.2 better than random Lift P -- percent of the list

7 KDD-CUP 1997 Task: given data on past responders to fund-raising, predict most likely responders for new campaign Population of 750K prospects 10K responded to a broad campaign mailing (1.4% response rate) Analysis file included a stratified (non-random) sample of 10K responders and 26K non-responders (28.7% response rate) 75% used for learning; 25% used for validation target variable removed from the validation data set

8 KDD-CUP 1997 Data Set 321 fields/variables with sanitized names and labels Demographic information Credit history Promotion history Significant effort on data preprocessing leaker detection and removal

9 KDD-CUP Participant Statistics 45 companies/institutions participated 23 research prototypes 22 commercial tools 16 contestants turned in their results 9 research prototypes 7 commercial tools

10 KDD-CUP Algorithm Statistics Of the 16 software/tools (Score as % of best) Algorithm # of Entries Ave. Score Rules 2 87 k-nn 1 85 Bayesian 3 83 Multiple/Hybrid 4 79 Other 2 68 Decision Tree 4 44

11 KDD Cup 97 Evaluation Best Gains at 40% Urban Science BNB Mineset Best Gains at 10% BNB Urban Science Mineset 11

12 KDD-CUP 1997 Awards The GOLD MINER award is jointly shared by two contestants this year 1) Charles Elkan, Ph.D. from University of California, San Diego with his software BNB, Boosted Naive Bayesian Classifier 1) Urban Science Applications, Inc. with their software gain, Direct Marketing Selection System The BRONZE MINER award went to the runner-up 3) Silicon Graphics, Inc with their software MineSet

13 KDD-CUP Results Discussion Top finishers very close Naïve Bayes algorithm was used by 2 of the top 3 contestants (BNB and MineSet) BNB and MineSet did little data preprocessing MineSet used a total of 6 variables in their final model Urban Science implemented a tremendous amount of automated data preprocessing and exploratory data analysis and developed more than 50 models in an automated fashion to get to their results

14 KDD Cup 1997: Top 3 results Top 3 finishers are very close 14

15 KDD Cup 1997 worst results Note that the worst result (C6) was actually worse than random. 15 Competitor names were kept anonymous, apart from top 3 winners

16 Better Model Evaluation? Comparing Gains at 10% and 40% is ad-hoc Are there more principled methods? Area Under the Curve (AUC) of Gains Chart Lift Quality Ultimately, financial measures: Campaign Benefits 16

17 Model Evaluation: AUC Area Under the Curve (AUC) is defined as the Difference between Gains and Random Curves Cum % Hits 17 Selection

18 Model Evaluation: Lift Quality AUC(Model) AUC(Random) LQ = AUC(Perfect) AUC(Random) See Measuring Lift Quality in Database Marketing, Piatetsky- Shapiro and Steingold, SIGKDD Explorations, December

19 Lift Quality (Lquality) For a perfect model, Lquality = 100% For a random model, Lquality = 0 For KDD Cup 97, Lquality(Urban Science) = 43.3% Lquality(Elkan) = 42.7% However, small differences in Lquality are not significant 19

20 Estimating Profit: Campaign Parameters Direct Mail example N -- number of prospects, e.g. 750,000 T -- fraction of targets, e.g B -- benefit of hitting a target, e.g. $20 Note: this is simplification actual benefit will vary C -- cost of contacting a prospect, e.g. $0.68 P -- percentage selected for contact, e.g. 10% Lift(P ) -- model lift at P, e.g. 3 20

21 Contacting Top P of Model-Sorted List Using previous example, let selection be P = 10% and Lift(P) = 3 Selection size = N P, e.g. 75,000 Random has N P T targets in first P list, e.g. 1,050 Q: How many targets are in model P-selection? Model has more by a factor Lift(P) or N P T Lift(P) targets in the selection, e.g. 3,150 Benefit of contacting the selection is N P T Lift(P) B, e.g. $63,000 Cost of contacting N P is N P C, e.g. $51,000 21

22 Profit of Contacting Top P Profit(P) = Benefit(P) Cost(P) = N P T Lift(P) B - N P C = NP (T Lift(P) B - C ) e.g. $12,000 Q: When is Profit Positive? C When T Lift(P) B > C, or Lift(P) > , e.g. 2.4 T B 22

23 Finding Optimal Cutoff 60 Use the formula to estimate benefit for each P Find optimal P Est Payoff

24 *Feasibility Assessment Expected Profit(P) depends on known Cost C, Benefit B, Target Rate T and unknown Lift(P) To compute Lift(P) we need to get all the data, load it, clean it, ask for correct data, build models,... 24

25 *Can Expected Lift be estimated? only from N and T? In theory -- no, but in many practical applications,?!?! surprisingly yes?!?! 25

26 *Empirical Observations about Lift For good models, usually Lift(P) is monotically decreasing with P Lift at fixed P (e.g. 0.05) is usually higher for lower T Special point P = T for a perfect predictor, all targets are in the first T of the list, for a maximum lift of 1/T What can we expect compared to 1/T? 26

27 *Meta Analysis of Lift 26 attrition & cross-sell problems from finance and telecom domains N ranges from 1,000 to 150,000 T ranges from 1% to 22% No clear relation to N, but there is dependence on T 27

28 *Results: Lift(T) vs 1/T Tried several linear and log-linear fits Best Model (R 2 = 0.86) log10(lift(t)) = log10(1/t) Approximately Lift(T) ~ T -0.5 = sqrt (1/T) 28

29 Lift *Actual Lift(T) vs sqrt(1/t) for All Problems Actual lift(t) Est. lift(t) Error = Actual Lift - sqrt(1/t) *T% Avg(Error) = St. Dev(Error) =

30 *GPS Lift(T) Rule of Thumb For targeted marketing campaigns, where 0.01 < T < 0.25, Lift(T) = sqrt (1/T) 1 Exceptions for truly predictable or random behaviors poor models information leakers 30

31 *Estimating Entire Curve Cumulative Percent Hits CPH(P) = Lift(P) * P CPH is easier to model than Lift Several regressions for all CPH curves Best results with regression log10(cph(p)) = a + b log10(p) Average R 2 =

32 *CPH Curve Estimate Approximately CPH(P) ~ sqrt(p) bounds: P 0.6 < CPH(P) < P

33 *Lift Curve Estimate Since Lift(P) = CPH(P)/P Lift(P) ~ 1/sqrt(P) bounds: (1/P ) 0.4 < Lift(P) < (1/P )

34 *More on Estimating Lift and Profitability G. Piatetsky-Shapiro, B. Masand, Estimating Campaign Benefits and Modeling Lift, Proc. KDD-99, ACM. 34

35 KDD Cup 1998 Data from Paralyzed Veterans of America (charity) Goal: select mailing with the highest profit Winners: Urban Science, SAS, Quadstone see full results and winner s presentations at 35

36 KDD-CUP-98 Analysis Universe Paralyzed Veterans of America (PVA), a not-forprofit organization that provides programs and services for US veterans with spinal cord injuries or disease, generously provided the data set PVA s June 97 fund raising mailing, sent to 3.5 million donors, was selected as the competition data Within this universe, a group of 200K Lapsed donors was of particular interest to PVA. Lapsed donors are individuals who made their last donation to PVA 13 to 24 months prior to the mailing 36

37 KDD Cup-98 Example Evaluation: Expected profit maximization with a mailing cost of $0.68 Sum of (actual donation-$0.68) for all records with predicted/ expected donation > $0.68 Participant with the highest actual sum wins 37

38 KDD Cup Cost Matrix Predicted Donation Yes No Actual Donation Yes DonationAmt No

39 KDD Cup 1998 Results Model Selecte d Result GainSmarts 56,330 $14,712 1 SAS 55,838 $14,662 2 Quadstone 57,836 $13,954 3 *ALL* 96,367 $10, #20 42,270 $1, #21 1,551 $ Rank Selected: how many were selected by the model Result: the total profit (donations-cost) of the model *ALL* - selecting all 39

40 Summary KDD Cup 1997 case study Model Evaluation: AUC and Lift Quality Estimating Campaign Profit *Feasibility Assessment GPS Rule of Thumb for Typical Lift Curve KDD Cup