How to Apply a Staggered Difference-in-Differences (DID) Design with Matching

[hussein bataineh]

I'm currently working on a project that examines the impact of Chief Sustainability Officer (CSO) presence on the relationship between pension (hard freezes) and CSR disclosures.

The design follows a published study framework, where the treatment sample includes the two years before and two years after each firm’s freeze event.

• Hard Freeze: An indicator variable equal to 1 if a firm freezes its defined benefit pension plan for all employees, and 0 otherwise. Firm-year observations after the freeze year for freeze firms are excluded from all analyses.
• CSO: A binary variable equal to 1 if the firm has a Chief Sustainability Officer, and 0 otherwise.
• FREEZE: Coded as 1 for firms that announce a DB pension freeze during the sample period.
• POST: Equals 1 for the year of the pension freeze and the two years following it, and 0 otherwise.

I'm planning to implement a staggered Difference-in-Differences (DiD) design to account for variation in treatment timing across firms. To improve covariate balance, I'm also applying matching. For each firm-year observation in the treatment group, I’m identifying a matched control firm from the same four-digit SIC industry, with similar firm size and year.im not sure how can i do this in STATA

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[CODE]
* Example generated by -dataex-. For more info, type help dataex
clear
input long id float(year hardfreezes freeeze posts postsXfreeze)
2 2004 0 0 0 0
2 2005 0 0 0 0
2 2006 0 0 0 0
2 2007 0 0 0 0
2 2008 0 0 0 0
2 2009 0 0 0 0
2 2010 0 0 0 0
2 2011 0 0 0 0
2 2012 0 0 0 0
2 2013 0 0 0 0
2 2014 0 0 0 0
2 2015 0 0 0 0
2 2016 0 0 0 0
2 2017 0 0 0 0
2 2018 0 0 0 0
2 2019 0 0 0 0
2 2020 0 0 0 0
2 2021 0 0 0 0
2 2022 0 0 0 0
3 2004 0 1 . .
3 2005 0 1 . .
3 2006 0 1 . .
3 2007 0 1 . .
3 2008 0 1 . .
3 2009 0 1 . .
3 2010 0 1 0 0
3 2011 0 1 0 0
3 2012 1 1 1 1
3 2013 . 1 1 1
3 2014 . 1 1 1
3 2015 . 1 . .
3 2016 . 1 . .
3 2017 . 1 . .
3 2018 . 1 . .
3 2019 . 1 . .
3 2020 . 1 . .
3 2021 . 1 . .
3 2022 . 1 . .
4 2004 . . . .
4 2005 . . . .
4 2006 . . . .
4 2007 . . . .
4 2008 . . . .
4 2009 . . . .
4 2010 . . . .
4 2011 . . . .
4 2012 . . . .
4 2013 . . . .
4 2014 . . . .
4 2015 . . . .
4 2016 . . . .
4 2017 . . . .
4 2018 . . . .
4 2019 . . . .
4 2020 . . . .
4 2021 . . . .
4 2022 . . . .
5 2004 . . . .
5 2005 . . . .
5 2006 . . . .
5 2007 . . . .
5 2008 . . . .
5 2009 . . . .
5 2010 . . . .
5 2011 . . . .
5 2012 . . . .
5 2013 . . . .
5 2014 . . . .
5 2015 . . . .
5 2016 . . . .
5 2017 . . . .
5 2018 . . . .
5 2019 . . . .
5 2020 . . . .
5 2021 . . . .
5 2022 . . . .
6 2004 0 0 0 0
6 2005 0 0 0 0
6 2006 0 0 0 0
6 2007 0 0 0 0
6 2008 0 0 0 0
6 2009 0 0 0 0
6 2010 0 0 0 0
6 2011 0 0 0 0
6 2012 0 0 0 0
6 2013 0 0 0 0
6 2014 0 0 0 0
6 2015 0 0 0 0
6 2016 0 0 0 0
6 2017 0 0 0 0
6 2018 0 0 0 0
6 2019 0 0 0 0
6 2020 0 0 0 0
6 2021 0 0 0 0
6 2022 0 0 0 0
8 2004 0 0 0 0
8 2005 0 0 0 0
8 2006 0 0 0 0
8 2007 0 0 0 0
8 2008 0 0 0 0
end
label values id id
label def id 2 "A", modify
label def id 3 "AAL", modify
label def id 4 "AAP", modify
label def id 5 "AAPL", modify
label def id 6 "ABBV", modify
label def id 8 "ABT", modify
[/CODE]
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