Gio Wiederhold PDM 4
1. Data Collection
Two choices
1.(rare)
Collect data specifically for analysis
§allows careful design --
Ømodel causes and effects
Purchase = f(price, color, size, custumer inc.,
gender,. ,,
×costly
×often small to make collection manageable
§imposes delays
2.(common)
Use data collected for other purposes
§take advantage of what is readily available
Ølow cost
×filtering, reformatting, integration
§incomplete - rarely covers all causes / effects
§biased -- missing categories
×only people with phones, cars -- shopping in
super markets