Currently MADiE gives a menu with two choices for improvement notation. QDM measures store improvement notation as text/plain in HQMF, for example,
<subjectOf>
<measureAttribute>
<code code="IDUR" codeSystem="2.16.840.1.113883.5.4">
<displayName value="Improvement Notation"/>
</code>
<value mediaType="text/plain" value="Improvement noted as an increase in rate"
xsi:type="ED"/>
</measureAttribute>
</subjectOf>

Below is a list of 17 ways that it is expressed in text/plain taken from Round 1 measure reviews for 2024 AU. The first one in the list occurs in 30 measures, the 2nd in 7 measures, etc. Note some that are not clearly increase or decrease, such as, "Within optimal range..."

1 30 "Higher score indicates better quality";
2 7 "A lower measure score indicates higher quality";
3 6 "A higher score indicates better quality";
4 5 "Improvement noted as an increase in rate";
5 5 "Higher score equals better quality";
6 3 "Lower score indicates higher quality, and a decreased score over time indicates improvement";
7 3 "Lower score indicates better quality";
8 2 "Improvement noted as a decrease in the rate";
9 1 "Within Optimal Range. The Joint Commission does not want to encourage inappropriately low Cesarean rates that may be unsafe to patients. Acceptable PC-02 rates are 30% or lower, however there is not an established threshold for what rate may be too low. PC-06 serves as a balancing measure for PC-02 to guard against any unanticipated or unintended consequences and to identify unforeseen complications that might arise as a result of quality improvement activities and efforts for this measure. In order to identify areas for improvement, hospitals may want to review results based on specific ICD-10 codes or patient populations. Data could then be analyzed further determine specific patterns or trends to help reduce cesarean births.";
10 1 "No actual measure score will be generated by hospitals. Instead, hospitals will report the data values for each of the CCDEs for all encounters in the Initial Population. These core clinical data elements will be linked to administrative claims data and used by CMS to calculate results for the Hybrid HWM measure.";
11 1 "No actual measure score will be generated by hospitals. Instead, hospitals will report the data values for each of the CCDEs for all encounters in the Initial Population. These CCDEs will be linked to administrative claims data and used by CMS to calculate results for the Hybrid HWR measure.";
12 1 "Improvement noted as an increase in the rate";
13 1 "Improvement noted as a decrease in the median value";
14 1 "Higher score indicates better quality of care";
15 1 "A meaningful improvement is a negative 3-point change in the urinary symptom score. The quality improves when a higher proportion of people meet the meaningful improvement definition.";
16 1 "A lower score indicates better quality";
17 1 "A higher score is the preferred result and indicates better quality";