Narrative:

I was working appleton (87) sector during a slow traffic volume time and I made a mistake that resulted in loss of separation. The incident happened as followed. We were metering to dtw and I had three dtw arrivals stacked vertically on top of one another and I needed to have all of them aob (at or below) FL300 before making hand off to ZOB ARTCC. I cleared air carrier X direct cvg VOR at FL320 who was moving from east to west at the time. Initially; I descended air carrier Y to FL330 to stay on top of air carrier X. For some reason all I could think about was I needed to get my dtw arrivals stepped down to meet the LOA (letter of agreement) of aob FL300. I descended air carrier Y to FL290 northbound direct bobct intersection. I then descended another dtw arrival to FL330 when I noticed air carrier Y left FL330 for FL290 overlooking air carrier X at FL320 westbound crossing in front of air carrier Y. A few moments later when I realized what I did... I tried to climb air carrier Y back to FL330 hoping I could get the separation I needed. Air carrier Y said he was climbing to FL330 on a RA he got from TCAS. Air carrier X then said he was descending to FL310 from a RA he received. Loss of separation occurred of 4.375 miles and resulted in a pilot error. I don't know why I overlooked air carrier X when I was staying above him initially. All I can think is that I was too worried about getting all dtw aircraft stacked on one another below FL300. For now on I will use a j-ball to keep me focused on the conflict I'm trying to separate from. I will definitely change my techniques after this pilot error. Using a j- ball on air carrier X would have helped me tremendously. I would have realized the aircraft that I needed to be cleared of to descend all of my dtw arrivals down. I wouldn't have overlooked it after initially stopping an aircraft 1000 feet above from the start.

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Original NASA ASRS Text

Title: There was a loss of separation event when a controller was concentrating on upcoming crossing restrictions with several DTW arrivals. The conflict was with enroute traffic.

Narrative: I was working Appleton (87) Sector during a slow traffic volume time and I made a mistake that resulted in loss of separation. The incident happened as followed. We were metering to DTW and I had three DTW arrivals stacked vertically on top of one another and I needed to have all of them AOB (at or below) FL300 before making hand off to ZOB ARTCC. I cleared Air Carrier X direct CVG VOR at FL320 who was moving from east to west at the time. Initially; I descended Air Carrier Y to FL330 to stay on top of Air Carrier X. For some reason all I could think about was I needed to get my DTW arrivals stepped down to meet the LOA (Letter of Agreement) of AOB FL300. I descended Air Carrier Y to FL290 northbound direct BOBCT Intersection. I then descended another DTW arrival to FL330 when I noticed Air Carrier Y left FL330 for FL290 overlooking Air Carrier X at FL320 westbound crossing in front of Air Carrier Y. A few moments later when I realized what I did... I tried to climb Air Carrier Y back to FL330 hoping I could get the separation I needed. Air Carrier Y said he was climbing to FL330 on a RA he got from TCAS. Air Carrier X then said he was descending to FL310 from a RA he received. Loss of separation occurred of 4.375 miles and resulted in a pilot error. I don't know why I overlooked Air Carrier X when I was staying above him initially. All I can think is that I was too worried about getting all DTW aircraft stacked on one another below FL300. For now on I will use a J-Ball to keep me focused on the conflict I'm trying to separate from. I will definitely change my techniques after this pilot error. Using a J- Ball on Air Carrier X would have helped me tremendously. I would have realized the aircraft that I needed to be cleared of to descend all of my DTW arrivals down. I wouldn't have overlooked it after initially stopping an aircraft 1000 feet above from the start.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.