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Multiple form versions

The simplest Task scenario is showing the same exact form to all of your workers. In that case you need to:

  • Compose task_data.json file containing definition of a single form (and place it into FormComposer config folder)
  • Optionally, verify your config: mephisto form_composer_config --verify
  • Run FormComposer: mephisto form_composer

But suppose you wish to show a slightly different version of the form to your workers. You can do so by defining multiple form versions. FormComposer provides several ways of doing so.

Custom form versions​

If your form versions vary considerably (e.g. showing different sets of fields), you should do the following steps:

  • Populate these form versions into task_data.json file manually (it will be basically a JSON array of N individual form versions configs)
  • Optionally, verify your config: mephisto form_composer_config --verify
  • Run FormComposer: mephisto form_composer

As a result, for each Task assignment Mephisto will automatically produce N units, each unit having a different form version. In total you will be collecting data from N * units_per_assignment workers.

Dynamic form config​

If your form versions vary only slightly (e.g. same set of fields, but showing different images or different text), you should use a dynamic form config as follows:

  • Ensure you populate these files, and place them into your FormComposer config folder:
    • form_config.json: tokenized form config - same as regular form config, except it will contain tokens within certain objects' attributes (see Tokens extrapolation)
    • token_sets_values_config.json: file containing sets of token values, where each set is used to generate one version of the form (and each form version will be completed by units_per_assignment different workers).
  • Optionally, verify your files: mephisto form_composer_config --verify
  • Generate task data config: mephisto form_composer_config --extrapolate-token-sets
    • This will overwrite existing task_data.json file with auto-generated form versions, by extrapolating provided token sets values
  • Run FormComposer: mephisto form_composer

The number of generated form versions N will be same as number of provided token sets. In total you will be collecting data from N * units_per_assignment workers.

Tokens extrapolation​

How does token extrapolation work?

A token is a named text placeholder that gets replaced ("extrapolated") by values specified in token_sets_values_config.json (each set of token values produces one form version based on dynamic form config form_data.json).

Token placeholders within an attribute are formatted like so: {{TOKEN_NAME}}

Tokens can be placed within the following object attributes:

  • help
  • instruction
  • label
  • title
  • tooltip

If you wish to reuse the same token across different form attributes and levels, it's enough to specify it in a set of token values just once. (This also means that token names must be unique within token values sets)

Generate token sets with --update-file-location-values​

In a special case when all of your tokens sets are simply permutations of several value lists, sets of token values can be easily auto-generated.

  • Populate your lists of values for every separate token into separate_token_values_config.json file
  • Optionally, verify your config: mephisto form_composer_config --verify
  • Generate token_sets_values_config.json with command: mephisto form_composer_config --permutate-separate-tokens

"Permutation" means all possible combinations of values. For example, permutations of amounts 2, 3, sizes big and animals cats, dogs will produce result 2 big cats, 2 big dogs, 3 big cats, 3 big dogs.

Generate separate token values with --update-file-location-values​

In a special case when one of your tokens is an S3 file URL, that token values can be easily auto-generated.

  • Make a public S3 folder that will contain only the files that you want (all of them)
  • Run command: mephisto form_composer --update-file-location-values S3_FOLDER_URL
  • As a result, a token with name "file_location" will be added to your separate_token_values_config.json config file. Its values will be S3 URLs of all files found .recursively within the S3_FOLDER_URL

Mturk Task Preview​

For Tasks run with Mechanical Turk provider, FormComposer generates a Task preview (a small HTML snippet shown to worker prior to starting the task). This Task review comprises HTML content of form object's attributes title and instruction.

However, note that the task preview is inherently static, therefore:

  • we always take the first form version in data_task.json to generate Task preview for all form versions
  • we erase dynamic tokens from the Task review content

Dynamic form config example​

Putting it altogether, this is a brief example of composing a dynamic form config.

Separate token values config​

Let's start with separate token values in separate_token_values_config.json file:

{
  "actor": ["Carrie Fisher", "Mark Hamill"],
  "movie_name": ["Star Wars"]
}

Token values config​

Permutating these token values will produce this form_config.json file with token sets values:

[
  {
    "tokens_values": {
      "actor": "Carrie Fisher",
      "movie_name": "Star Wars"
    }
  },
  {
    "tokens_values": {
      "actor": "Mark Hamill",
      "movie_name": "Star Wars"
    }
  },
]

Example of config after using --update-file-location-values "https://s3.amazonaws.com/...." --use_presigned_urls params:

[
  {
    "tokens_values": {
      "file_location": "{{getPresignedUrl(\"https://s3.amazonaws.com/1.jpg\")}}"
    }
  },
  {
    "tokens_values": {
      "file_location": "{{getPresignedUrl(\"https://s3.amazonaws.com/2.jpg\")}}"
    }
  },
]

Form config​

These tokens are placed into the form_config.json dynamic form config like so:

{
  ...
  "instruction": "Rate {{actor}}'s performance in movie <b>'{{movie_name}}'</b>",
  ...
  "help": "Please only consider the movie '{{movie_name}}'",
  ...
}
...
{
  ...
  "instruction": "Rate the plot in movie '{{movie_name}}' out of 10",
  ...
}

Task data config​

After extrapolating attributes from form_config.json with token sets from token_sets_values_config.json, we get the resulting task_data.json file used for the task:

// First extrapolated form version
{
  ...
  "instruction": "Rate Carrie Fisher's performance in movie <b>'Star Wars'</b>",
  ...
  "help": "Please only consider the movie 'Star Wars'",
  ...
}
...
{
  ...
  "instruction": "Rate the plot in movie 'Star Wars' out of 10?",
  ...
},
// Second extrapolated form version
{
  ...
  "instruction": "Rate Mark Hamill's performance in movie <b>'Star Wars'</b>",
  ...
  "help": "Please only consider the movie 'Star Wars'",
  ...
}
...
{
  ...
  "instruction": "Rate the plot in movie 'Star Wars' out of 10?",
  ...
}