Understanding Society User Support

I have set up a panel data using 18 waves of r_ecstat files. These files are part of the Derived Current and Annual Net Household Income data set, an unofficial supplement to the set of derived income variables in
the official BHPS release.

I am not sure what exactly the scale of the issue is for what percentage of the constructed panel the problem exists but by quickly browsing through the data I spotted many cases like the following:

tab butype if pid==10017992
benefit unit type | Freq. Percent Cum.
------------------------+-----------------------------------
couple,1 ch,m lt 65 | 6 35.29 35.29
f lone parent,lt 60 | 2 11.76 47.06
single woman,lt 20 | 2 11.76 58.82
single woman,20-39 | 7 41.18 100.00
------------------------+-----------------------------------

Or another example:
tab butype if pid==10016848

benefit unit type Freq. Percent Cum.

benefit unit type |      Freq.     Percent        Cum.
------------------------+-----------------------------------
couple,no ch,m lt 65    |          8       53.33       53.33
couple,1 ch,m lt 65     |          5       33.33       86.67
single woman,20-39      |          2       13.33      100.00
------------------------+-----------------------------------

I was not expecting to observe the same PID for these individuals but maybe there is a simple explanation here or I might be misunderstanding some thing.

Any help is greatly appreciated!

Shilan Dargahi wrote:

I have set up a panel data using 18 waves of r_ecstat files. These files are part of the Derived Current and Annual Net Household Income data set, an unofficial supplement to the set of derived income variables in
the official BHPS release.

I am not sure what exactly the scale of the issue is (for what percentage of the constructed panel the problem exists) but by quickly browsing through the data I spotted many cases like the following:

tab butype if pid==10017992
benefit unit type | Freq. Percent Cum.
------------------------+-----------------------------------
couple,1 ch,m lt 65 | 6 35.29 35.29
f lone parent,lt 60 | 2 11.76 47.06
single woman,lt 20 | 2 11.76 58.82
single woman,20-39 | 7 41.18 100.00
------------------------+-----------------------------------

Or another example:
tab butype if pid==10016848

benefit unit type Freq. Percent Cum.

benefit unit type | Freq. Percent Cum.
------------------------+-----------------------------------
couple,no ch,m lt 65 | 8 53.33 53.33
couple,1 ch,m lt 65 | 5 33.33 86.67
single woman,20-39 | 2 13.33 100.00
------------------------+-----------------------------------

I was not expecting to observe the same PID for these individuals but maybe there is a simple explanation here or I might be misunderstanding some thing.

Any help is greatly appreciated!