Rethinking this string of comments. Is the QDM description in Appendix B.2 really incorrect, or is the logic missing critical information. E.g., if the desire is that the order for medication happens at least 1 minute after the order for the pregnancy test, the logic should state that fact (consistent with Appendix B2 as written). Though more complex, it could be written to include another timing requirement:
> 1 minute(s) starts after end of "Occurrence A of Laboratory Test, Order: Pregnancy Test".
Please confirm with the measure developer, but this seems to be a more explicit set of logic rather than expecting an implementer to read through multiple examples in the QDM specification to interpret the intent correctly.

I agree the interpretation from David Czulada is partially correct. In this example, the intent is to indicate seconds or minutes after the test is performed through the end of 7 days after the test (presumably to the end of the 7th day, not to 7 x 1440 minutes). The QDM section B.2. is explicit to indicate what to do if "no calculation unit is defined." In this case, the logic needs to be more explicit if there is to be a timing difference of 1 minute. I agree further clarity with examples in the QDM specification will help. However, I also think the measure developer should consider the intent. The reason for the exclusion is because a pregnancy test is performed for the purpose of determining if the pregnancy is performed solely for evaluating if isoretinon could be used or an Xray performed. While the QDM spec could be more expressive, the timing relationship is used rather than looking for the reason for the lab test is to determine a risk for treatment. Clinical workflow may not provide such information in the real world so the timing relationship is a surrogate for the information actually desired. I might ask if the result of the pregnancy test should be known before ordering the isoretinon or the Xray and, therefore, timing to one second or one minute may not be ideal. In the grand scheme of things, the "starts after or concurrent" is probably as effective as "starts after the end of". The actual difference is minute especially since this is a surrogate logic statement. One might question the cost of calculating such precision and consider how many extra exclusions would be captured if the logic were set to a day as described in the QDM.

Unfortunately, the QDM documentation on this topic is as clear as mud.

I believe the intent of QDM for this particular example would be:

• Minutes is used first to determine that the relationship (starts after end) is true,
• And then the delta is calculated in the given unit (days) to see if the comparison is true.

If this is in-fact the intent of QDM, the spec needs to be updated to be more explicit. The spec does not make assertions, or show any examples, where an unstated time unit of measurement is used for the relationship comparison and the stated date unit is used to calcuate the duration comparison. However, the fourth example does specifically state that the unit specified is intended for the calculation of “duration" between the two date/time stamps.

If the above is not the intent of QDM, the measure should be updated to "starts after or concurrent” in places where units less granular than minute(s) are used.

QDM is consistent is specifying that all times are in fact times, and not solely dates. In every instance where time comparisons are used they are specified as "date/time”.

-Dave Czulada

I don’t agree with your interpretation of Appendix B when it comes to handling temporal operators. B.2 specifically says that if no time unit is given, you use minutes. That implies that the temporal operator must also respect the given time units.
See the examples from Appendix B.2:
Example 1: Granularity to Seconds
A: 2012-01-01 11:00:01
B: 2012-01-01 11:00:02 A
starts before B = TRUE

Example 2: Granularity to Minutes
A: 2012-01-01 11:00
B: 2012-01-01 11:00
A starts before B = FALSE

This implies that the result starts before operator will change based on the time unit you are using. The examples you give seem to imply that the temporal operator should always be based on minutes, which conflicts with Appendix B.

I believe the line in question in CMS-153 should be changed from this:
<= 7 day(s) starts after end of "Occurrence A of Laboratory Test, Order: Pregnancy Test"
To this:
<= 7 day(s) starts after or concurrent with end of "Occurrence A of Laboratory Test, Order: Pregnancy Test"
This would clear up any confusion with the measure logic.

​

Using the 'starts after end of' timing restricts the logic to ensure that the event on the left-hand side (LHS) starts temporally AFTER the end of the event on the right-hand side (RHS), and not concurrently. The further restriction of '<= 7 day(s)' then evaluates whether the LHS falls within this range. Per Appendix B.1, two events that occur on the same day will result in a duration of 0 days. Zero days falls within the '<= 7 day(s)' criteria and the logic is met. (Page 31 of the QDM explains these steps.)

A <= 7 day(s) starts after end of B

Example 1
Event A starts at 02/09/2015 11:00
Event B ends at 02/09/2015 10:00

• Does A start after the end of B? Yes
• Is A <= 7 day(s) after B? Yes - duration is 0 days
• Criteria is met

Example 2
Event A starts at 02/09/2015 11:00
Event B ends at 02/09/2015 12:00

• Does A start after the end of B? No
• Criteria is not met

Example 3
Event A starts at 02/09/2015 11:00
Event B ends at 02/09/2015 11:00

• Does A start after the end of B? No
• Criteria is not met

Your solution contradicts that last portion of Appendix B.2 of the QDM guide (second half of page 76), which says that if a unit is specified in the criterion, that unit should be used as the default unit for calculation. Since the unit of days is defined in ">= 7 days", we should be using a granularity of days.

If these data elements are calculated to the granularity of a day, this means labs that occur on the same day as the med or xray would appear to happen concurrently. This does not meet the "starts after end" requirement.

Link to guide: https://ecqi.healthit.gov/system/files/qdm/qdm_4_1_2.pdf