Analysing Post codes and Zip codes
There are a few golden rules when analysing Post codes and Zip codes:
You must remember that Snap is case sensitive, so, if the data has been entered in a variety of ways (e.g. BS8, bs8 or even Bs8), you will need to enter all possible variations in order to capture all the data.
It is always best to enter each variety of post code / zip code in inverted commas (e.g. "BS8 9QT").
The best way of analysing post codes / zip codes is to create a Derived Single variable and you should apply the following golden rules, when using a derived single:
If your post codes / zip codes include letter combinations that could be found in another post code (e.g. B7 and BS7), you should put the more complex codes before the simpler ones (i.e. BS7 should be inserted before B7).
If your post codes / zip codes include number combinations that could be found in another post code (e.g. SW1 and SW11), you should put a space after the shorter code (e.g. "SW1 " and "SW11").
To create your variable please use the following procedure:
Step By Step
Step 1
From the Variables window click 
to add a new variable.
Step 2
Specify the Variable Details:
| Name: | V9 |
| Label: | Area |
| Type: | Derived |
Step 3
Response: Single (each respondent will only fall into one of the new codes)
Step 4
Specify the Code details:
1 RG3 4 Q10="RG3 4"
2 BS7 Q10="BS7" or Q10="bs7"
3 BS1 Q10="BS1 " or Q10="bs1"
4 BS11 Q10="BS11" or Q10="bs11"
Step 5
B1 Q10="B1" or Q10="b1"
If you wish to check your results you may do so, by using the Filter button 
in the Data window. Using the example above, you could enter a filter value of V9=1 to ensure you have specified the value correctly for the post code / zip code RG3 4.