Added “Date To Be Mailed” field to Survey API

We have updated our API and of course all the changes are non-breaking ;-). Beside the usual performance improvements, one of the changes worth mentioning here is the addition of the new “DateToBeMailed” field. This allows you to add multiple contacts to a survey but have them invited at different times.

This can be useful for several different scenarios:

  • You may want contacts to receive an e-mail invitation at a certain time of day in their time zone to improve response rates. Some large companies process transactions from the day in batch at night. During the batch process, they call our API to send out e-mail invitations to customers with which they had contact. This works great, but it also means that the mails go out during the night. Unfortunately 3am is not a great time to send an e-mail. The recipient only sees it in their mailbox in the morning, under a pile of other mails and newsletters that have arrived during the night. Setting the mail to arrive at 10am in the recipient’s time zone will increase the chance that they see it and open it.
  • You may have a transaction, like an online- or phone sale where the transaction is not really complete until the purchased items arrive. In that case you want to delay the e-mail invitation from going out so that the customer can evaluate the whole process including delivery.
  • You may be a travel agency. Customers book with you well in advance. In that case you only want the e-mail invitation to go out once the person returns from their journey.

I’m sure there are many more scenarios that our user base will think of. If you have a good one, please share here below…


Join the conversation
  • john marie butas - December, 2018 reply

    hello, i’ve got 5 known population here as given below.
    CITY A=2 619 362
    CITY B=447 156
    CITY C=382 853
    CITY D=245 466
    CITY E=115 75
    my sample size is 400. what would be the sample size percentage of each known population above so i would know how many respondents I’m going to survey in those particular cities?

    Gert Van Dessel - December, 2018 reply

    You can use our sample size calculator to calculate sample sizes for different populations, confidence levels and margins of error (often confidence level 95% and MoE 5% is taken).

  • Aruna - November, 2016 reply

    Good Morning
    I am doing Marketing Research. I have distributed more than 700 questionnaire and I received 250 fully completed ones. I am going to take that as my sample size. which formula should I follow? .

    Maarten Marijnissen - November, 2016 reply


    The formula to calculate sample size is: n = Z² x p x (1-p)/M²

    n = Sample Size for infinite population
    Z = Z value (e.g. 1.96 for 95% confidence level)
    P = population proportion (expressed as decimal) (assumed to be 0.5 (50%)
    M = Margin of Error at 5% (0.05)

    When you know the number of respondents you can calculate the margin of error. This number tells you how much the opinions of your sample are likely to deviate from the population.
    You can calculate it using the second part of our sample size calculator. Fill in the population size, number of respondents and confidence level en your margin of error will show.

    Good luck!

    Ambes Shimellis - February, 2017

    First of all thank you for your quick reply! while using this sample size determination furmula for our research, how we cite the this formula?

    Maarten Marijnissen - February, 2017

    Hi, you’re welcome!

    The formula is from Cochran: Cochran, W.G.(1977), Sampling Techniques, 3rd ed., John Wiley & Sons.

    Good luck with your research!

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