Accurate CPM or Critical Path Method schedules adhere to several construction scheduling rules.  A mechanically correct construction schedule meets the following criteria.

Open Ends. Only 2 are allowed.  The first activity and the last activity do not have a predecessor or successor.  Request or create a reports that includes the predecessor and success or columns.  If there are more than 2 open ends, then the schedule may not be producing accurate completion dates.   

No Out of Sequence Logic - An activity should not finish before its predecessor if it is a finish to start relationship.  This can occur if an activity is worked out of sequence in the field, it may have an actual start or finish date. When this occurs, the relation should be broken or modified to represent the correct flow of logic.  You can run a report to show out-of-sequence logic and it should be corrected.

Use of lags - lags should be used minimally and long duration negative lags should avoided.

Update period.  Every schedule should be updated daily, weekly,  or monthly.  The number of activities in progress, type of project, and the construction team's needs often determine how often a schedule is updated.

Total Float - Show the total float column.  Activities in a series or chronological sequence should have the same or similar float.  If you see a group of activities that has total float numbers that are not similar, it may indicate an open end.