Comparison

NASA PVT+ vs Reflex

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

NASA PVT+

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
Read full description

The official NASA PVT+ (Psychomotor Vigilance Test) is a validated iOS based touchscreen PVT that includes multiple industry standard research forms for collecting a wide range of research data for sleep, alertness and performance studies. The app has three principle data collection schemes designed to accomidate a wide range of research studies. The Simple PVT: The Simple PVT is a single presentation of the Psychomotor Vigilance Test (PVT; described below). Participants can be instructed to take a PVT at any time. There is no limit to the number of PVTs that a participant can take. Basic Study: The Basic Study provides a single or multiday pre-set framework for collecting research data. Participants are prompted to complete a sleep diary after their main sleep episode. The participant is then prompted to complete three PVT and Karolinska Sleepiness Scale (KSS) responses during the day. The participants also complete a sleep diary before bed. Aviation Study: The Aviation Study provides a multiday pre-set framework for collecting aviation related research data. Split into Off-Duty Days and Duty Days. Participants are prompted to complete a sleep diary after their main sleep episode. The participant is then prompted to complete three PVT and KSS responses during off-duty days. On duty days, the participant is prompted to complete a PVT and KSS pre- and post-duty. They are also prompted to complete a PVT, KSS, hassle factors, use of fatigue countermeasures, and inflight rest at the top of descent for each flight. The participants also complete a sleep diary before bed. The number of flights within a duty day can be adjusted. The aviation study also includes a pre-study baseline questionnaires that can be completed at study enrollment. The specific components of the application include: - Psychomotor Vigilance Test (PVT): A simple reaction-timed test that is sensitive to sleep loss and circadian misalignment. The PVT displays a box on the screen and participants are instructed to tap the screen with their dominant thumb when a millisecond counter appears in the box and begins to count up. After the participant taps the screen, the counter briefly displays the reaction time in milliseconds, then the counter disappears, and the participant is instructed to refrain from touching the screen until the next millisecond counter appears in the box. The counter appears randomly every 2 to 10 seconds. The PVT can be configured by the investigator to the desired duration (currently validated for a 5-minute test). - Karolinska Sleepiness Scale (KSS): The KSS is a self-reported sleepiness rating where the participant is asked to rate their level of sleepiness within the last five minutes on a scale from 1 to 9. - Sleep Diary: The Basic Study and Aviation Study each include a sleep diary that the study participant is prompted to complete at the beginning and at the end of the main sleep episode. The pre-sleep sleep diary asks the participant to record any naps that were taken prior to the main sleep episode, along with indicating the time of bedtime. The post-sleep sleep diary asks the participant to record the time that it took to fall asleep, number and duration of night awakenings, final wake time, and a sleep quality rating. - Study Enrollment Information: The Aviation Study includes a demographic questionnaire and the Morningness-Eveningness Questionnaire along with a practice sleep diary and practice PVT to orient the participant to study procedures. Data collected from study participants using the NASA PVT+ iOS application does not include Personally Identifiable Information (PII). Research data is never collected directly by NASA unless a volunteer is participating in a NASA study. Data collected for research studies conducted outside of NASA, through use of the NASA PVT+ application, is never sent to NASA without a specific agreement between the outside organization and NASA.

About

Reflex

Read full description

Reflex measures in 20 seconds how sharp your mind is today – and shows you over weeks what really affects your reactions: sleep, activity, resting heart rate, HRV, coffee or exercise. One test a day, one number, one clear picture. NO ACCOUNT. NO TRACKING. NO ADS. All data stays on your device. Apple Health is only read, never shared and never stored in iCloud. The daily test is free and always will be. 20 SECONDS A DAY Tap as soon as the screen turns green – as fast as you can. Reflex measures the moment your finger touches the screen, detects false starts and lapses, and takes the median of all reactions. The method is a compact form of the Psychomotor Vigilance Task that sleep researchers use to measure alertness. YOUR DAY AT A GLANCE The Today tab shows your score compared to your 7-day average, your streak, your best and the day's health context: last night's sleep, yesterday's steps, resting heart rate, HRV and when you woke up. HISTORY OVER WEEKS Trend chart with moving average and personal best, every session with all trials in detail. A weekly recap sums up average, best day and the comparison to last week – shareable as an image. WHAT MAKES YOU FASTER After seven days with data, Reflex calculates the relationship between your reaction time and each health metric: "From 7 h of sleep: 8% faster." Not from studies, but from your own numbers. EXPERIMENTS Tag days with coffee, alcohol, exercise, stress or little sleep – and see what makes the difference for you. DAILY FORECAST In the morning, Reflex predicts from your sleep and heart data what today has in store. After the test you see whether you did better than expected. WIDGET, SIRI, REMINDER Home and Lock Screen widgets with today's score and streak, the "Start Reflex test" shortcut for Siri and the Action button, and a daily reminder only on days you haven't tested yet. REFLEX PRO – €7.99 PER YEAR OR €19.99 ONCE • All insights in detail: steps, resting heart rate, HRV, time since waking • Daily forecast "expected vs. actual" • Experiments: with and without coffee, exercise, alcohol • Patterns by weekday and time of day • Unlimited history, CSV export, weekly recap as an image • iCloud sync of your test results across your devices The yearly plan starts with 7 days free. The sleep insight and the daily test always stay free. Reflex is not a medical device. Its analyses show relationships in your own data and do not replace medical advice. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy: https://csappworks.de/reflex/datenschutz

Screenshots

NASA PVT+4 screens
Reflex4 screens

Verdict

The call

The clearest difference is in-app purchases: NASA PVT+ at none against Reflex's 2. NASA PVT+ also leads on device support (3 vs 1) and iOS requirement (13.6 vs 18.0). Reflex's advantage is update cadence (every 2 days vs every 3 months). On price and ads there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Reflex sells 2 in-app purchases, starting at $6.99 per year. NASA PVT+ asks for nothing beyond the download.

UpkeepUpdate frequency

NASA PVT+ ships an update every 3 months, Reflex every 2 days. Both last shipped on October 24, 2026.

Scorecard4 real differences · 6 level
NASA PVT+ versus Reflex: the parameters behind the verdict, then further details
ParameterNASA PVT+Reflex
PriceFreeFree
Rating4.8 (10 ratings) — better—
Positive reviews25.0% of reviews—
Number of ratings10 — better—
Update frequencyEvery 3 monthsEvery 2 days — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree—
DevicesiPhone, iPad, iPod — betteriPhone
Requires iOS13.6 — better18.0
Further details — not scored
Size31 MB2 MB
Age rating4+4+
DeveloperNASACarsten Schaal

In-app purchases

None

NASA PVT+

No in-app purchases

2 purchases

Reflex

Subscriptions1
  • Reflex Pro – Yearly7 Days trial$6.991 Year
One-time1
  • Reflex Pro – Lifetime$17.99

Questions

Is NASA PVT+ free?
NASA PVT+ is free to download, with no in-app purchases.
Is Reflex free?
Reflex is free to download, with in-app purchases available.
Do NASA PVT+ or Reflex have ads?
Neither NASA PVT+ nor Reflex shows ads.
Which is updated more often, NASA PVT+ or Reflex?
NASA PVT+ ships an update every 3 months, and Reflex every 2 days. Most recently, NASA PVT+ was updated on October 24, 2026 and Reflex on October 24, 2026.

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