Hello,

I have this panel with a monthly date that I converted to a quarterly date. I want to keep all the observations for each NDC. When I use the command
Code:
collapse (mean) shortage, by( qdate )
I got only 23 observations. So, how to keep 23 qdate for each NDC?

Code:
* Example generated by -dataex-. For more info, type help dataex
clear
input str16 NDC long date float(qdate shortage NDCid)
"00002-7597-01" 664 221 0 2
"00002-7597-01" 665 221 0 2
"00002-7597-01" 666 222 0 2
"00002-7597-01" 667 222 0 2
"00002-7597-01" 668 222 0 2
"00002-7597-01" 669 223 0 2
"00002-7597-01" 670 223 0 2
"00002-7597-01" 671 223 0 2
"00002-7597-01" 672 224 0 2
"00002-7597-01" 673 224 0 2
"00002-7597-01" 674 224 1 2
"00002-7597-01" 675 225 1 2
"00002-7597-01" 676 225 1 2
"00002-7597-01" 677 225 1 2
"00002-7597-01" 678 226 1 2
"00002-7597-01" 679 226 1 2
"00002-7597-01" 680 226 1 2
"00002-7597-01" 681 227 1 2
"00002-7597-01" 682 227 1 2
"00002-7597-01" 683 227 1 2
"00002-7597-01" 684 228 0 2
"00002-7597-01" 685 228 0 2
"00002-7597-01" 686 228 0 2
"00002-7597-01" 687 229 0 2
"00002-7597-01" 688 229 0 2
"00002-7597-01" 689 229 0 2
"00002-7597-01" 690 230 0 2
"00002-7597-01" 691 230 0 2
"00002-7597-01" 692 230 0 2
"00002-7597-01" 693 231 0 2
"00002-7597-01" 694 231 0 2
"00002-7597-01" 695 231 0 2
"00002-7597-01" 696 232 0 2
"00002-7597-01" 697 232 0 2
"00002-7597-01" 698 232 0 2
"00002-7597-01" 699 233 0 2
"00002-7597-01" 700 233 0 2
"00002-7597-01" 701 233 0 2
"00002-7597-01" 702 234 0 2
"00002-7597-01" 703 234 0 2
"00002-7597-01" 704 234 0 2
"00002-7597-01" 705 235 0 2
"00002-7597-01" 706 235 0 2
"00002-7597-01" 707 235 0 2
"00002-7597-01" 708 236 0 2
"00002-7597-01" 709 236 0 2
"00002-7597-01" 710 236 0 2
"00002-7597-01" 711 237 0 2
"00002-7597-01" 712 237 0 2
"00002-7597-01" 713 237 0 2
"00002-7597-01" 714 238 0 2
"00002-7597-01" 715 238 0 2
"00002-7597-01" 716 238 0 2
"00002-7597-01" 717 239 0 2
"00002-7597-01" 718 239 0 2
"00002-7597-01" 719 239 0 2
"00002-7597-01" 720 240 0 2
"00002-7597-01" 721 240 0 2
"00002-7597-01" 722 240 0 2
"00002-7597-01" 723 241 0 2
"00002-7597-01" 724 241 0 2
"00002-7597-01" 725 241 0 2
"00002-7597-01" 726 242 0 2
"00002-7597-01" 727 242 0 2
"00002-7597-01" 728 242 0 2
"00002-7597-01" 729 243 0 2
"00002-7597-01" 730 243 0 2
"00002-7597-01" 731 243 0 2
"00003-0371-13" 664 221 0 3
"00003-0371-13" 665 221 0 3
"00003-0371-13" 666 222 0 3
"00003-0371-13" 667 222 0 3
"00003-0371-13" 668 222 0 3
"00003-0371-13" 669 223 0 3
"00003-0371-13" 670 223 0 3
"00003-0371-13" 671 223 0 3
"00003-0371-13" 672 224 0 3
"00003-0371-13" 673 224 0 3
"00003-0371-13" 674 224 0 3
"00003-0371-13" 675 225 0 3
"00003-0371-13" 676 225 0 3
"00003-0371-13" 677 225 0 3
"00003-0371-13" 678 226 0 3
"00003-0371-13" 679 226 0 3
"00003-0371-13" 680 226 0 3
"00003-0371-13" 681 227 0 3
"00003-0371-13" 682 227 0 3
"00003-0371-13" 683 227 0 3
"00003-0371-13" 684 228 0 3
"00003-0371-13" 685 228 0 3
"00003-0371-13" 686 228 1 3
"00003-0371-13" 687 229 1 3
"00003-0371-13" 688 229 1 3
"00003-0371-13" 689 229 1 3
"00003-0371-13" 690 230 1 3
"00003-0371-13" 691 230 1 3
"00003-0371-13" 692 230 1 3
"00003-0371-13" 693 231 1 3
"00003-0371-13" 694 231 1 3
"00003-0371-13" 695 231 1 3
end
format %tm date
format %tq qdate
label values date Time1
Thank you