A metropolitan hospital implemented rigorous protocols to reduce the number of needlestick injuries. These injuries can occur when medical professionals draw blood, administer medications, or dispose of used needles. To monitor the effectiveness of new protocols, hospital staff record the date and time of each needlestick injury.

The staff create a T chart to monitor the rate of needlesticks.

  1. Open the sample data, NeedleSticks.MTW.
  2. Choose Stat > Control Charts > Rare Event Charts > T.
  3. In Variables, enter Date and time of needlestick.
  4. Click OK.

Interpret the results

One point failed Test 2 (9 points in a row on same side of center line). The rate of needle sticks was lower than expected during this time.

T Chart of Date and time of needlestick

Test Results for T Chart of Date and time of needlestick

TEST 2. 9 points in a row on same side of center line. Test Failed at points: 39 * WARNING * If graph is updated with new data, the results above may no longer be correct.
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