FICO and VantageScore count both closed and open accounts on one's report when calculating AAoA (average age of accounts), AoYA (age of youngest account), and AoOA (age of oldest account). Credit Karma's front end software gets this wrong and uses only open accounts.
Karma also botches utilization. FICO always rounds up, e.g. 2.1% becomes 3%. Karma will round 2.1% down to 2%. Other sites, including sites that provide FICO scores, have also been known to do this.
Don't confuse the way FICO handles account age stats with the way it handles number/percentage of cards reporting positive balances. For number/percentage of cards reporting positive balances, FICO considers only open accounts.
