Provided by Danielle and copied from: http://cmceast.org/resources/numbering-measures.php
Participants and coaches are expected to number measures in their parts and scores in advance of the Conference, so that groups can make better use of coaching time. Being able to locate a starting point quickly and unambiguously allows us to work more efficiently during coachings and rehearsals, especially when members of the group are working from different editions.
Measure number totals and numbering guidance may have been provided to you on your Tentative Coaching Schedule. If so, be sure to follow the guidance and to check that your totals match those you’ve been given.
If you are using an edition that contains measure numbers, check whether the numbers follow the Conference conventions, and if they do not, adjust the numbering where needed.
How to Number Measures
There is no universally-agreed-upon system for counting measures. The following scheme is frequently found in pre-numbered parts and can be applied successfully in almost all cases:
- Place a bar number either at the beginning of each line or every ten bars; you don’t need to number each bar.
- Count the beginning of each measure. Do not count any partial measure at the start of a movement. Always check the number of beats in the first bar to be sure.
- If a measure is divided across a double bar, across a repeat, across a change of clef, key or meter, or from one staff system to the next, be sure not to count it twice. Don’t count subdivisions within measures marked by dotted lines.
- At a repeat with first and second endings, don’t count the first ending. In general, count only the last in a set of endings.
- Count trios, codas or variations in continuity with the preceding printed measures, even if they are not played in that sequence; do not restart from 1. Count tacet parts in trios or variations in accordance with the score.
- Count each movement individually.
Possible Problems, Possible Solutions
Q: How do I know I’ve numbered properly?
A: The only way to be reasonably certain that you have numbered properly is to prepare two separate parts or to number with a partner. The score is the easiest part to do correctly, so start with that.
Q: What if the first ending is long, and we want to be able to refer to a measure contained in the first ending? You’ve told us not to number any ending except the last!
A: Okay, here’s the fancier version of that rule: the measures in the first ending have a suffix a attached to the bar number, whereas the second ending starts at the same bar number as the first ending but with a b suffix, and so forth.
Q: What if a repeat is written out in one part?
A: This particular editorial decision poses problems for bar numbering. In this case the most straight-forward plan is that bar numbers should be re-used in the part written out: different instances of the same bar should have the same number. If you have only your own part and the score, however, you may not be aware of the layout in other parts or other editions. Fortunately this occurs infrequently.
Q: What if the bar lines are unaligned in the different parts?
A: Usually this can be discerned only by looking at the score. In this case, one should count only those bar lines held in common by all parts. It is very valuable in such spots to place a number over each common bar line, rather than just once per line, so that you will quickly see the common starting points.
Q: What if the parts contain cuts?
A: Another problem. The group may need to work from a single edition and should count each bar therein.