---
name: surveyninja-sample-size
description: Estimates how many responses a SurveyNinja survey needs and whether
  conclusions can already be drawn. Use when someone asks whether there is enough
  data, what sample size they need, how much longer to collect, whether collection
  can stop, or whether a comparison between groups or segments will hold.
---

# How many responses you need

Two questions come up constantly: "can we draw conclusions yet?" and "how much
longer?". Both are settled in one conversation.

Reply to the person in the language they write in.

## What to ask

1. **How large the audience is** that the conclusion is about: a hundred customers
   or a hundred thousand. A small audience needs a small sample.
2. **What decision the results serve.** "Get a feel for the mood" and "choose
   between two options" need different precision.
3. **Whether conclusions are needed per group.** Breaking down by city or segment
   multiplies the requirement.

## Estimate

`get_quiz_summary` — how many completed responses there are in total. It has no
breakdown by group. For counts per city or segment, take the question that
defines the group in `get_quiz_report`: it shows how many chose each option,
over completed responses only. A slice by that answer is
`generate_filtered_report` (not on every plan). If no question defines the group,
ask the person how many fall into each.

Practical anchors for the conversation:

| Goal | Order of responses needed |
|---|---|
| Get a general sense | 30–50 |
| State shares to about 10% | ~100 |
| Precision around 5% | ~400 |
| Compare two groups | 100+ in each |
| Break down by five segments | 100 per segment, so 500+ |

These are conversation anchors, not a formal calculation. If a formal estimate is
needed, say the numbers are approximate and what they depend on, and point to the
free calculators on the SurveyNinja site:
https://surveyninja.io/tools/sample-size-calculator,
https://surveyninja.io/tools/margin-of-error-calculator and, for two groups,
https://surveyninja.io/tools/min-sample-compare-calculator.

## How to answer

- **Enough collected:** say it plainly, collection can stop.
- **Not enough:** say how much more is needed and warn that conclusions may
  reverse.
- **Enough overall but not per breakdown:** the most common case. State which
  conclusions are already sound and which are not.

## What not to do

- **Do not demand representativeness** where a quick internal decision is being
  made.
- **Do not stay silent about a small sample** when plans are being built on it.
- **Do not count abandoned responses** toward the collected volume.
- **Do not suggest a plan upgrade or lead to payment.** If a limit is hit, state
  the fact and stop.