[cem] How to get matched pairs from CEM?

Hi, I am using Coursened Exact Matching to improve balance in my sample. The summary matching results after applying CEM are that 11,128 pixels have been matched: Sample sizes: Control Treated All 19741 8283 Matched 6728 4400 Unmatched 13013 3883 Discarded 0 0 Firstly, is it possible to specify 1:1 matching with CEM? I want to only retain matched pairs, which requires the same amount of pixels in my treatment & control groups. I am also having trouble getting a unique identifier for each matched pair so that I can calculate the difference between the treatment and control. I am using the code: pair: Produces a paired sample out of a CEM match solution When I execute the below command, it says there are 0 matches. Total number of units paired in CEM strata: 0 Total number of units matched: 0 Can anyone help or point me in the right direction? Thanks, Tori Victoria Graham | MPhil., PhD candidate Macquarie University NSW 2109 Australia T: +61 2 9850 6298 | E: victoria.graham@mq.edu.au<mailto:victoria.graham@mq.edu.au> Twitter:@ToriFGraham<https://twitter.com/ToriFGraham> [cid:image001.png@01D5F150.30032D90]