Why my own calculation differs from the dashboard

The extra reporting/analysis done based on raw data report gives percentages with 2 decimals (e.g. 31.52%). The dashboard shows whole percentages (e.g. 31%). If you take the 2-decimal value and round it yourself, you can end up with a different number than the one we show. This is expected.

1. Multiple choice (does not add up to 100%)

Each answer is rounded on its own, from the unrounded value. A .5 is rounded up.

Example

101 respondents, 51 selected answer A.

	Result
Unrounded	51 / 101 × 100 = 50.4950…%
Rounded to 2 decimal points	50.4950… → 50.50%
Rounded to whole number	50.4950… → 50%

50.50% appears to be 51% if also rounded to whole number, making user think the dashboard result is wrong. But the difference comes from rounding twice: first to 2 decimals, then to a whole number.

2. Single choice (adds up to 100%)

If we rounded each answer on its own, the total could be 99% or 101%. To keep it at 100%, the dashboard

Rounds all percentages down.
Calculates how many points are missing to reach 100.
Adds 1 point to the answers with the largest decimals, one by one, until the total is 100. If two answers have the same decimals, the answer that appears later in the list goes first.
Calculates promoter % and detractor % from the counts.
Rounds each of them to a whole number (.5 is rounded up, away from zero).
Calculates rounded eNPS = rounded promoter % − rounded detractor %.
Calculates passive % = 100 − promoter % − detractor %, so the three always add up to 100%.

This means that an answer of 31.52% can be shown as 31% (while it appears to be closers to 32%).

Example

92 respondents, one answer each.

Answer	Count	Extra report	Step 1: round down	Step 3: extra point	Dashboard
A	29	31.52%	31	— (decimals .52, smallest)	31%
B	30	32.61%	32	+1 (decimals .61)	33%
C	33	35.87%	35	+1 (decimals .87, largest)	36%
Total	92	100.00%	98 → 2 points missing		100%

When you look at each answer yourself from the 2 decimal result from extra reporting done based on raw data, you get 101% if rounded to 0 decimal like the dashboard.

3. eNPS

eNPS = % promoters (9–10) − % detractors (0–6). The dashboard:

Example

600 respondents: 91 promoters, 236 passives, 273 detractors.

		Raw Data Analysis Result (from 2 decimals)	Dashboard
Promoters	91 / 600 = 15.17%	15.17%	15.17 → 15%
Detractors	273 / 600 = 45.50%	45.50%	45.50 → 46%
Passives	236 / 600 = 39.33%	39.33%	100 − 15 − 46 = 39%
eNPS		15.17 − 45.50 = −30.33 → −30	15 − 46 = −31

If you subtract first and round after that, you get −30. The dashboard rounds the two percentages first and then subtracts, so it shows −31. With this method, the eNPS always matches the promoter and detractor percentages that you see on screen (15% − 46% = −31).