A gap is not a zero
Missing information should remain visible in the interpretation.
The short answer
A connecting line can make the gap look resolved even when it is not. Label missing dates and distinguish interpolation from measurement. The interval between points matters when describing speed of change.
A worked example
A series records January 100, February 110 and April 120. March is not recorded. Filling March with 0 invents a collapse. Filling it with 115 invents an estimate. Neither is an observed value.
Your turn
Write a note using only known values. “The recorded value increased by 20 between January and April; March is unavailable” preserves the evidence without guessing.
What this does not tell you
An illustrative calculation does not explain causes or predict future results. Check the dates, units and missing observations before using the method elsewhere.
Related term
Missing valueSources & review
Original Charts Haven example. All stated numbers are illustrative and allow you to repeat the calculation.
Next lesson: Check the period