# NASA PVT+ vs AlertMeter

The clearest difference is rating: NASA PVT+ at 4.8 against AlertMeter's 4.4. NASA PVT+ also leads on iOS requirement (13.6 vs 16.4). AlertMeter's advantage is review sentiment (50% vs 25%) and update cadence (monthly vs every 3 months). On price, ratings volume, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

NASA PVT+ holds the better App Store score, 4.8 against 4.4. Both are backed by a comparable volume of ratings — 10 and 15 respectively. Written reviews complicate that: 25% of NASA PVT+'s written reviews are positive against 50% of AlertMeter's, so the app with the better star average is not the one people write more warmly about.

NASA PVT+ ships an update every 3 months, AlertMeter monthly. The most recent releases landed on August 15, 2026 and September 8, 2026 respectively.

## The numbers

| Metric | NASA PVT+ | AlertMeter |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.8 (10 ratings)](https://appshunter.io/ios/app/nasa-pvt-plus/id1146834402/reviews)** | [4.4 (15 ratings)](https://appshunter.io/ios/app/alertmeter/id1179939295/reviews) |
| Number of ratings | 10 | **15** |
| Positive reviews | 25.0% of reviews | **50.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Monthly** |
| Monetization | Free | Free |
| Size | 31 MB | 25 MB |
| Requires iOS | **13.6** | 16.4 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [NASA](https://appshunter.io/developer/355542146) | [Predictive Safety SRP, Inc.](https://appshunter.io/developer/1179939294) |

## What reviewers say

### NASA PVT+

[App page](https://appshunter.io/ios/app/nasa-pvt-plus/id1146834402)

This app provides a validated tool for conducting psychomotor vigilance tests, crucial for sleep, alertness, and performance research. It offers multiple study frameworks, including simple tests, basic multi-day studies, and specialized aviation research protocols.

**Highlights:** Psychomotor Vigilance Test (PVT), Karolinska Sleepiness Scale (KSS), Sleep Diary, Simple PVT mode, Basic Study framework, Aviation Study framework

**Features:** Vision Pro support

**In-app purchases:** none


### AlertMeter

[App page](https://appshunter.io/ios/app/alertmeter/id1179939295)

This app helps identify when fatigue, illness, medication, or distraction may impact cognitive function. It allows individuals to regularly test their alertness levels, providing companies with a daily overview of employees in critical roles. The app is designed to respect employee privacy while assessing fitness for work.

**Highlights:** Personalized alertness testing, Company-wide daily overview, Privacy-respecting employee monitoring, Identifies impact of fatigue/illness, Assesses fitness for safety-critical roles

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is NASA PVT+ free?

NASA PVT+ is free to download, with no in-app purchases.

### Is AlertMeter free?

AlertMeter is free to download, with no in-app purchases.

### Which has better reviews, NASA PVT+ or AlertMeter?

NASA PVT+ is rated higher. NASA PVT+ averages 4.8 out of 5 from 10 ratings, while AlertMeter averages 4.4 from 15 ratings.

### Do NASA PVT+ or AlertMeter have ads?

Neither NASA PVT+ nor AlertMeter shows ads.

### Which is updated more often, NASA PVT+ or AlertMeter?

NASA PVT+ ships an update every 3 months, and AlertMeter monthly. Most recently, NASA PVT+ was updated on August 15, 2026 and AlertMeter on September 8, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*