Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Supported by

The last component of the study does not want to finish and save the data

Dear All,

I have an experiment where the last component is just simple Screen HTML with just a message on the screen. And its timeout was set to 500 ms. Of the 4 participants who participated, the data was saved only for two, but for two the last component remained "forever" on the screen and the page with "This study is finished. Thank you for your participation" does not want to load. That's why I lost those two participants because it is pointless to participate twice in this research. What could have caused this behavior of JATOS? The experiment is complex and consists of over 20 components (several questionnaires, several tests programmed in JavaScript, etc.) and I also collect data about mouse movements in "event stream" form. So the final txt file with the results of one participant has about 4 MB. However, I repeat, for two participants the data was stored and everything went fine (!?) So what could have caused this problem?

Thank you very much for your reply,



  • Hi Marko,

    That is unfortunate. Let's have a look. What do you mean with "its timeout was set to 500 ms"? This isn't one of JATOS' features, is it? It seems to be a component with only a few lines of code: Maybe you could post them here?



  • Hi Kristian,

    It is feature from lab.js. A timeout can be set for each component in the Behavior tab (see picture ->). I am normally using that to finish the experiment and write down the results.


  • Hi Kristian again,

    Now I have another doubt: I use the VDC (Virtual Data Center) of our University on which we are allowed to install what we want. So I installed JATOS on it. And now I see that that server is "Not secured". Is it possible that this prevents saving the results?

    Thank you again,


  • I can't imagine a scenario where a server without HTTPS does prevent your data from being saved, especially after you successfully run several other components.

    So, this 500ms timeout is a feature of lab.js. I would need to see the actual source code that lab.js produces. I suspect the culprit is there. Can you please post it here? Or if you can't find it, send me the whole experiment file (if you prefer privately).

  • I sent you a private message.

  • I got your message and it contains a zip with a JSON file. But the JSON file is not what's running in a browser. I assume that is what lab.js produces? I'd need an actual JATOS archive (click the Export button in JATOS UI).

  • Ok, I sent you it privately.

    Thank you,


  • Dear Kristian,

    I've moved the research from our university's JATOS to Mindprobe and it seems to work fine there. Some problem seems to be on our server.


  • Dear Kristian,

    Unfortunately, it doesn't even work on Mindprobe. Sometimes the data is written, sometimes not. I don't see the logic at all. Please help,


  • Hi Marko, I had hope to find something in your code, but since your experiment is in lab.js and lab.js is minified and difficult to debug I couldn't find anything. I suspect there is a problem in how lab.js handles your (short) timeout and using of jatos.js' study flow functions, but again their is no easy way for me to check. You could head over to lab.js' Slack channel but it seems to be down: Another thing that comes to my mind is to put your last lab.js component into an JATOS component: there you have full control over it but you have to do it yourself in HTML/JS. But don't know how feasible this is for you. Sorry, I couldn't help any further.

  • Hi Kristian, First, thanks so much for trying to help! I have just one more question. You say this: "I suspect there is a problem in how lab.js handles your (short) timeout and using of jatos.js' study flow functions..." Does this mean that the experiment could be more stable if I set timeout of the last component to a longer time instead of 500ms? Thanks in advance for your reply, Marko

  • Could be. It's a hunch.

    Another thing that comes to my mind: have you updated to the latest version of JATOS? It fixes a bug (maybe not really a bug actually), where participants cannot finish it's study in case they have a bad internet connection and even after 5x retrying to send the result data doesn't help. Without the fix jatos.js just stops at this point - with the fix jatos.js tries to continue (and accept the temporary data loss) with the next request. I'm not sure this will help in your case.

  • Greetings,

    First of all, I transferred the study to Mindprobe and I had a problem with Mindprobe. So it's not up to JATOS (if you maintain JATOS properly :-)). And now I can finish by explaining how I solved the problem: After I split the study into two parts and after each part has a little more than 2 mb of data (instead of over 4 mb in total) everything works fine. However, it is not good that there is such a problem on JATOS (even on Mindprobe). The whole problem was due to the "excessive" amount of data being collected. I don't know if the problem is in JATOS, data transfer or even in the browser, but the problem obviously exists.


  • Hi Marko! Hm. JATOS has by default a upper limit of 5 MB per sending of result data (by using jatos.submitResultData or jatos.appendResultData). Are you sure about the 2 MB size of your data? Maybe they are 2 MB in a file on your computer but larger when send over the network? Anyway, there is an easy way to circumvent this quota: send your data in several chunks via jatos.appendResultData (or use jatos.uploadResultFile). Best, Kristian

Sign In or Register to comment.

agen judi bola , sportbook, casino, togel, number game, singapore, tangkas, basket, slot, poker, dominoqq, agen bola. Semua permainan bisa dimainkan hanya dengan 1 ID. minimal deposit 50.000 ,- bonus cashback hingga 10% , diskon togel hingga 66% bisa bermain di android dan IOS kapanpun dan dimana pun. poker , bandarq , aduq, domino qq , dominobet. Semua permainan bisa dimainkan hanya dengan 1 ID. minimal deposit 10.000 ,- bonus turnover 0.5% dan bonus referral 20%. Bonus - bonus yang dihadirkan bisa terbilang cukup tinggi dan memuaskan, anda hanya perlu memasang pada situs yang memberikan bursa pasaran terbaik yaitu Bola168. Situs penyedia segala jenis permainan poker online kini semakin banyak ditemukan di Internet, salah satunya TahunQQ merupakan situs Agen Judi Domino66 Dan BandarQ Terpercaya yang mampu memberikan banyak provit bagi bettornya. Permainan Yang Di Sediakan Dewi365 Juga sangat banyak Dan menarik dan Peluang untuk memenangkan Taruhan Judi online ini juga sangat mudah . Mainkan Segera Taruhan Sportbook anda bersama Agen Judi Bola Bersama Dewi365 Kemenangan Anda Berapa pun akan Terbayarkan. Tersedia 9 macam permainan seru yang bisa kamu mainkan hanya di dalam 1 ID saja. Permainan seru yang tersedia seperti Poker, Domino QQ Dan juga BandarQ Online. Semuanya tersedia lengkap hanya di ABGQQ. Situs ABGQQ sangat mudah dimenangkan, kamu juga akan mendapatkan mega bonus dan setiap pemain berhak mendapatkan cashback mingguan. ABGQQ juga telah diakui sebagai Bandar Domino Online yang menjamin sistem FAIR PLAY disetiap permainan yang bisa dimainkan dengan deposit minimal hanya Rp.25.000. DEWI365 adalah Bandar Judi Bola Terpercaya & resmi dan terpercaya di indonesia. Situs judi bola ini menyediakan fasilitas bagi anda untuk dapat bermain memainkan permainan judi bola. Didalam situs ini memiliki berbagai permainan taruhan bola terlengkap seperti Sbobet, yang membuat DEWI365 menjadi situs judi bola terbaik dan terpercaya di Indonesia. Tentunya sebagai situs yang bertugas sebagai Bandar Poker Online pastinya akan berusaha untuk menjaga semua informasi dan keamanan yang terdapat di POKERQQ13. Kotakqq adalah situs Judi Poker Online Terpercayayang menyediakan 9 jenis permainan sakong online, dominoqq, domino99, bandarq, bandar ceme, aduq, poker online, bandar poker, balak66, perang baccarat, dan capsa susun. Dengan minimal deposit withdraw 15.000 Anda sudah bisa memainkan semua permaina pkv games di situs kami. Jackpot besar,Win rate tinggi, Fair play, PKV Games