# Are cumulative sums approximate?
**URL:** https://discuss.elastic.co/t/are-cumulative-sums-approximate/66215
**Category:** Elasticsearch
**Created:** [November 16, 2016, 7:43am UTC](https://discuss.elastic.co/t/are-cumulative-sums-approximate/66215 "2016-11-16T07:43:07Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@WoJ](https://discuss.elastic.co/u/WoJ)
#### Post date: [November 16, 2016, 7:43am UTC](https://discuss.elastic.co/t/are-cumulative-sums-approximate/66215/1 "2016-11-16T07:43:07Z")
Hello,
I calculate a cumulative sum via `cumulative_sum`:
```
{
"size":0,
"aggs":{
"vulns_day":{
"date_histogram":{
"field":"HOST_START_iso",
"interval":"day"
},
"aggs":{
"dates_stats":{
"stats":{
"field":"HOST_START_iso"
}
},
"vulns_cumulated":{
"cumulative_sum":{
"buckets_path":"dates_stats.count"
}
}
}
}
}
}
```
During the last days there were no new events indexed and despite this the cumulative sum shows progress. As an example (to highlight the scale of the change) on day `n` there were `2,406,013` accumulated events and on `n+1` - `2,411,455`. This is a change of `5,442` events (where the change was supposed to be 0), or about `0.2%`.
**I have seen in the past that some of the information provided by ES was not exact by design, I wonder if this would not be such a case as well?**
(initially asked on [SO](http://stackoverflow.com/questions/40615399/are-cumulative-sums-approximate))
Thank you!
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [December 14, 2016, 7:43am UTC](https://discuss.elastic.co/t/are-cumulative-sums-approximate/66215/2 "2016-12-14T07:43:40Z")
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