data is not reliably saved

[Geoff-McK]

Hi everyone,

I am running a study using jsPsych, and saving the data to a server. The problem is that although the data are often saved when I try it, and is saved for about 66-80% of the participants who submit the survey code on MTurk, there are still about 20-30% of participants less data files than submitted assignments. It doesn't appear that there is any "funny business" on their end. I should mention that I don't seem to have any problems saving demographics data, and I had no problem with this when I used this code for undergraduates (also online).

I am wondering why this might happen. It appears that this occurs more often early on after publishing the HIT rather than later. Given that this is the time when a lot of people participate, I am thinking that it may be a bottleneck issue.

Any feedback would be greatly appreciated.

Thanks.

Here is some of the code that is used for saving data:

function prepdata(data) {
  var datacsv = "";
  var labels = Object.keys(data); //grabs all the properties of data

  for (n = 0; n < labels.length; n++){
    datacsv = datacsv + labels[n] + ','; // 'col1', 'col2'
  }
  datacsv = datacsv + '\n'; //next line

  // console.log("ntoloop: " + data[Object.keys(data)[0]].length)
  // console.log("data_all.length: " + data.test_face.length)
  let ntoloop = data.test_face.length // data[Object.keys(data)[0]].length;
  console.log(data)
  for (n = 0; n < ntoloop; n++){
    for (var i in data){
      if (data.hasOwnProperty(i)){
        datacsv = datacsv + data[i][n] + ','; //in "str" + num, num is converted to a string.

        // console.log("data: " + data[i][n])
        // console.log("i: " + i)
        // console.log("n: " + n)


      }
    }
    datacsv = datacsv + '\n';
  }

  return datacsv;
};


function prep_demo_data(data) {
  var datacsv = "";
  var labels = Object.keys(data); //grabs all the properties of data

  for (n = 0; n < labels.length; n++){
    datacsv = datacsv + labels[n] + ','; // 'col1', 'col2'
  }
  datacsv = datacsv + '\n'; //next line

  let ntoloop = data[Object.keys(data)[0]].length;
  // console.log(data)
  for (n = 0; n < ntoloop; n++){
    for (var i in data){
      if (data.hasOwnProperty(i)){
        datacsv = datacsv + data[i][n] + ','; //in "str" + num, num is converted to a string.

        // console.log("data: " + data[i][n])
        // console.log("i: " + i)
        // console.log("n: " + n)


      }
    }
    datacsv = datacsv + '\n';
  }

  return datacsv;
};


var subNum_demo = subNum; //subject id will be different for demo and for experiment data
var demofilename = "MTurk_demo_" + String(subNum_demo);


//save demographic data to server folder
function saveDemoData(name, data){
  var xhr = new XMLHttpRequest();
  xhr.open('POST', 'FamSearch_demo_writedata.php'); // 'write_data.php' is the path to the php file
  xhr.setRequestHeader('Content-Type', 'application/json');
  xhr.send(JSON.stringify({filename: name, filedata: data}));
}

function savethedemodata() {
  //save cleaned data
  saveDemoData(demofilename, prep_demo_data(data_demo));
}

var save_demo_data = {
  type: 'call-function',
  func: savethedemodata
}

rsvp_task.push(save_demo_data);

//save data to server folder
function saveData(name, data){
  var xhr = new XMLHttpRequest();
  xhr.open('POST', 'FamSearch_writedata.php'); // 'write_data.php' is the path to the php file
  xhr.setRequestHeader('Content-Type', 'application/json');
  xhr.send(JSON.stringify({filename: name, filedata: data}));
}



function savethedata() {
  //save cleaned data
  // console.log("data.all: " + data_all.condition[0])
  saveData(datafilename, prepdata(data_all));
}

var save_data = {
  type: 'call-function',
  func: savethedata,
  
	on_start: function(){
			var today = new Date();
	}
}
   
rsvp_task.push(save_data);

My php files:

FamSearch__writedata.php (which is identical to FamSearch_demo_writedata.php):

<?php
$post_data = json_decode(file_get_contents('php://input'), true);
// the directory "data" must be writable by the server
$name = "data/".$post_data['filename'].".csv";
$data = $post_data['filedata'];
// write the file to disk
file_put_contents($name, $data);
?>

[jodeleeuw]

Do you have any trials in your timeline after the data are saved? If the participant is closing the browser window or moving to another page immediately after the save data trial is called then the request might cancel before it is completed.

[Geoff-McK]

I don't think so. Below is code that may show that this is the case:

//save data to server folder
function saveData(name, data){
  var xhr = new XMLHttpRequest();
  xhr.open('POST', 'FamSearch_writedata.php'); // 'write_data.php' is the path to the php file
  xhr.setRequestHeader('Content-Type', 'application/json');
  xhr.send(JSON.stringify({filename: name, filedata: data}));
}



function savethedata() {
  //save cleaned data
  // console.log("data.all: " + data_all.condition[0])
  saveData(datafilename, prepdata(data_all));
}

var save_data = {
  type: 'call-function',
  func: savethedata,
  
	on_start: function(){
			var today = new Date();
			// data_all.Exp_end_time.push(today.getHours() + ":" + today.getMinutes() + ":" + today.getSeconds());

	
	}
}
   
rsvp_task.push(save_data);

var debriefing_form = {
  type:'external-html',
  url: "https://acl.psychology.gatech.edu/jspsych-6.1.0/examples/debriefingform.html",
  cont_btn: "end" // id of continue button, trial advances when this is clicked
   
};

rsvp_task.push(debriefing_form);


var survey_link = {
	type: "html-keyboard-response",
  stimulus: "YOUR SURVEY CODE IS: " + rand_string,
  choices: jsPsych.NO_KEYS
}

rsvp_task.push(survey_link);


var all_faces = faces.concat(practice_faces)

jsPsych.init({
    timeline: rsvp_task,
	preload_images: all_faces,
	exclusions: {
			min_width: 1200,
			min_height: 400
		},
    on_finish: function() {
   }

    // use_webaudio: false
});