Re: st: Draw an offer curve (supply curve)?

["Brian P. Poi" <bpoi@stata.com>]

G. Dai wrote:
> Dear all,
> I have a dataset on real offering behavior and I want to draw an
> offering curve (supply curve) from the data set.
> One simple example of the data is following:
>
> ID    Qantity_Offered    Price_asked
>
> 1       10                         99
> 2        23                        90
> 1        5                          50
> 4       30                         32
> 3       39                         10
> 2       30                          0
> 4       20                          0
> 3       20                          0
>
> ID is the individual participating in the trade, and quantity_offered
> is the quantity they can offer at the price of Price_asked.
> We can see some individuals just ask zero price for some quantities,
> while ask a higher price for extra quantities.  My object is draw an
> offer curve (supply curve) from the data in an efficient way because
> the dataset  is big.
>
> Any suggestion is appreciated.
> Thanks and have a great weekend!

How about something like this:

. input id q p
1       10                         99
2        23                        90
1        5                         50
4       30                         32
3       39                         10
2       30                          0
4       20                          0
3       20                          0
end

. sort p                  // put data in ascending price order
. gen totalq = sum(q)     // running sum of total quantity offered
                          // for price <= p
. line p totalq, connect("stairstep")


Brian P. Poi
Senior Economist
StataCorp LP

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