updated readme

README.md

@@ -1,10 +1,56 @@
-# deid-risk
+# Re-Identification Risk
 
-The code below extends a data-frame by adding it the ability to compute de-identification risk (marketer, prosecutor).
-Because data-frames can connect to any database/file it will be the responsibility of the user to load the dataset into a data-frame.
+This framework computes re-identification risk of a dataset assuming the data being shared can be loaded into a dataframe (pandas)
+The framework will compute the following risk measures:
+    - marketer
+    - prosecutor
+    - pitman
 
+References :
+
+    [http://ehelthinformation.ca](http://www.ehealthinformation.ca/wp-content/uploads/2014/08/2009-De-identification-PA-whitepaper1.pdf)
+    [https://www.scb.se/contentassets](https://www.scb.se/contentassets/ff271eeeca694f47ae99b942de61df83/applying-pitmans-sampling-formula-to-microdata-disclosure-risk-assessment.pdf)
+
+This framework integrates pandas (for now) as an extension and can be used in two modes :
+* 1. explore: *
+    Here the assumption is that we are not sure of the attributes to be disclosed, 
+    The framework will explore a variety of combinations and associate risk measures every random combinations it can come up with
+
+* 2. evaluation: *
+    Here the assumption is that we are clear on the sets of attributes to be used and we are interested in computing the associated risk.
+
+
+# Four risk measures are computed :
+
+    - Marketer risk
+    - Prosecutor risk
+    - Journalist risk
+    - Pitman Risk
+
+# Usage:
+
+    import numpy as np
+    import pandas as pd
+    from pandas_risk import *
+
+    mydf = pd.DataFrame({"x":np.random.choice( np.random.randint(1,10),50),"y":np.random.choice( np.random.randint(1,10),50) })
+    print mydf.risk.evaluate()
+
+
+
+    #
+    # computing journalist and pitman
+    #   - Insure the population size is much greater than the sample size 
+    #   - Insure the fields are identical in both sample and population
+    #
+    pop = pd.DataFrame({"x":np.random.choice( np.random.randint(1,10),150),"y":np.random.choice( np.random.randint(1,10),150) ,"q":np.random.choice( np.random.randint(1,10),150)})
+    mydf.risk.evaluate(pop=pop)
+
+@TODO:
+    - Evaluation of how sparse attributes are (the ratio of non-null over rows)
+    - Have a smart way to drop attributes (based on the above in random policy search)
 Basic examples that illustrate usage of the the framework are in the notebook folder. The example is derived from 
-[http://ehelthinformation.ca](http://www.ehealthinformation.ca/wp-content/uploads/2014/08/2009-De-identification-PA-whitepaper1.pdf)
+
 
 Dependencies:
 	numpy