Unit 02.01: Who is reading it and what they already know

The same finding needs a different chart for each audience, and this is not a matter of taste.

What they already know, and what they need

Four audiences for one finding, with what each brings and what each needs.

The code lays them out.

AUDIENCES = [
    ("the analyst who built the pipeline",
     "everything", "can read a box plot; wants the raw distribution"),
    ("the department head",
     "the metric and its target", "wants the exception and the cause"),
    ("the executive committee",
     "the metric exists", "wants one number and one comparison"),
    ("an external customer",
     "nothing about your internals", "needs units and scope spelled out"),
]
print(f"{'reader':34} {'already knows':28} needs")
for reader, knows, needs in AUDIENCES:
    print(f"{reader:34} {knows:28} {needs}")

print("""
The same finding needs a different chart for each row. That is not a
presentation preference -- a box plot shown to the executive committee will be
misread, and a single big number shown to the analyst withholds what they
needed.
""")

A box plot shown to an executive committee will be misread; a single large number shown to the analyst withholds exactly what they needed. Both are correct charts for the wrong reader.

The external row is the one people forget. A customer knows nothing about your internal definitions, so every unit and scope has to be spelled out rather than assumed.

The mistake this prevents

The mistake is building one chart and presenting it to everyone, adjusting only the commentary. The chart type itself carries an assumption about what the reader can decode, and commentary does not repair a misread chart.

Takeaway

Decide who is reading before choosing the chart. What they already know determines how much the chart must explain, and what they will decide determines what it must show.

Mark complete