Dismiss Notice
You must be a registered member in order to post messages and view/download attached files in this forum.
Click here to register.

Control chart applicable?

Discussion in 'SPC - Statistical Process Control' started by DRSAMI, Jun 8, 2019.

  1. DRSAMI

    DRSAMI New Member

    Joined:
    Jun 8, 2019
    Messages:
    2
    Likes Received:
    0
    Trophy Points:
    1
    I am preparing monthly the percentage of compliance with a standard related to radiologists reporting TAT. I have easy access to all data so there is no sampling at all. Despite the absence of sampling, it is possible to use control charts to detect trends in the monthly results, by using for example individual results and moving range

    Thanks
     
  2. essegn

    essegn Member

    Joined:
    Feb 5, 2016
    Messages:
    36
    Likes Received:
    3
    Trophy Points:
    7
    yes, it is possible to detect trends or to find out if your process is stable or not.
    Please be aware to choose the correct charts (i suposse the p-chart in your case) and data need to be time-ordered.
    Optional you can implement detection rules - read the article: When Should We Use Extra Detection Rules? | Quality Digest
     
  3. Bev D

    Bev D Moderator Staff Member

    Joined:
    Jul 30, 2015
    Messages:
    426
    Likes Received:
    450
    Trophy Points:
    62
    Location:
    Maine
    My response from Elsmar:

    TAT = Turn Around Time? Is this a set time on the clock (for example the radiologist must submit their report by 9 AM) or is it teh allowed time to complete the report from the time of submission (for example, the readiologist has 2 hours from the submission to submit their report).

    Yes an I, MR chart will work for TAT compliance. The subgroup for what I have described above is typically a day, but weeks and months will also work.

    If TAT is what I described above, more insightful chart is to plot the actual time it took the radiologist to complete the analysis for each individual submission. You can still use an I, MR chart.

    As a point of clarification, sampling error is only a convenient way of ‘describing’ the variation from subgroup to subgroup from an infinite real process stream. (It derives from actual sampling error when taking small samples from a finite population). In real life we have actual process variation as well as ‘sampling error’ when taking small samples from an infinite stream of work. Control charts still work for these infinite streams because the variation of the process is ‘random’ and homogenous.
     
    tony s likes this.
  4. DRSAMI

    DRSAMI New Member

    Joined:
    Jun 8, 2019
    Messages:
    2
    Likes Received:
    0
    Trophy Points:
    1
    Reporting TAT a radiology KPI defined as following:
    from the time radiology exam is completed by tech until report finalized by the radiologist

    our benchmarks are 2 hours for urgent exams, 24 hours for inpatients and 48 hours for outpatients.
    we are computing monthly the percents of compliance with these benchamarks based on all the reports.
    for our department we have per month roundly 300 urgent cases, 1000 inpatients and 3000 patients
     
  5. Bev D

    Bev D Moderator Staff Member

    Joined:
    Jul 30, 2015
    Messages:
    426
    Likes Received:
    450
    Trophy Points:
    62
    Location:
    Maine
    You might find the following article useful:

    What About p-charts?”, by Donald Wheeler, published by Quality Digest.

    he describes why the I MR chart is so useful and the limitations of the p chart even for proportional data. certain assumptions do need to be met to use the p chart and the I MR chart has fewer assumptions.
     
  6. tony s

    tony s Well-Known Member

    Joined:
    Sep 10, 2015
    Messages:
    959
    Likes Received:
    725
    Trophy Points:
    92
    Location:
    Laguna Philippines
    You may need to chart separately the urgent exams, inpatients and outpatients since they have different TAT benchmarks.
     

Share This Page