
source/field **ex %** p r

airport code 100 1.0 1.0

airport name 90 1.0 1.0

Amazon author 100 97.3 **0.92** Amazon title 70 98.8 **0.81**

Amazon price 100 1.0 **0.99**

Amazon ISBN 100 1.0 **0.91**

Amazon availability 60 1.0 **0.86**

Barnes&Noble author 100 0.93 **0.96**

Barnes&Noble title 80 0.96 **0.62**

Barnes&Noble price 90 1.0 **0.68**

Barnes&Noble ISBN 100 1.0 **0.95**

Barnes&Noble availability 90 1.0 **0.92**

Bigbook name 70 1.0 **0.76**

Bigbook street 90 1.0 **0.87** Bigbook city 70 0.91 **0.98**

Bigbook state 100 0.04 **0.50**

Bigbook phone 90 1.0 **0.30**

mapquest time 100 1.0 **0.98**

mapquest distance 100 1.0 **0.98**

Quote pricechange 50 0.38 **0.36**

Quote ticker 63 0.93 **0.87**

Quote volume 100 1.0 **0.88**

Quote shareprice 38 0.46 **0.60** Smartpages name 80 1.0 **0.82** Smartpages street 80 1.0 **0.52** Smartpages city 0 0.68 **0.58**

Smartpages state 100 1.0 **0.70**

Smartpages phone 100 0.99 1.0

Y ahoo Quote pricechange 100 1.0 **0.41**

Y ahoo Quote ticker 100 1.0 **0.98**

Y ahoo Quote volume 100 1.0 **0.99**

Y ahoo Quote shareprice 80 1.0 **0.59**

Washington Post price 100 1.0 1.0

Weather temp 40 0.36 **0.82**

Weather outlook 90 0.83 1.0

average 83 0.90 **0.80**

Table 8: Reinduction results on ten Web sources. The first column lists the fraction of the fields for each source that were correctly extracted by the pattern-based algorithm. We judged the field to be extracted if the algorithm correctly identified at least two examples of it. The last two columns list precision and recall on the data extraction task using the reinduced wrappers.