Immigrant Visa Waiting Times Addendum

November 11, 2010

Señor Kermit Romeo Erasmus, just as a quick followup to my previous post, here’s the histogram of waiting times for the CR1 visa based on the same data.  This appears very much to be the waiting time distribution for a tandem queue, with the second peak being a second interview I believe.  Clearly different types of visas have different waiting time distributions. It would be an interesting source separation problem to try to figure out all of the different immigrant visa waiting time distributions from case data that is not labeled by visa type when you have prior information that the signals are waiting times from queues.  I don’t think anyone has looked at that problem.  Even the simpler case in which the signals are single delayed gamma distributions with unknown parameters would be interesting.

Bo Zhang and I talked about possible interfaces between queueing theory and machine learning a bit last week, but unfortunately this idea didn’t come to me before our discussion.

Before signing off, let me congratulate the IBM Research team that just won the Wagner Prize at the INFORMS Annual Meeting.  (I wasn’t at the meeting in person, but was there in spirit.)



  1. […] Ashvins The Ultimate Machinists « Immigrant Visa Waiting Times Addendum Point Processes and Tandem Queues November 15, […]

  2. hello sir,

    i m beneficial of cr1 visa. my husband is us citizen and he requested to nvc for do expedite process for my file due to personal resons after we received (choice of agent) from national visa center . then nvc mail letter to my husband that


    [ your inquiry has been received at the nvc
    The u.s Embassy/consulate General has acceoted this case as an expedite.
    This file will be immediately forwarded to the u.s. Embassy/consulate General any further quetion regarding processing or interview appointment date should di directed to the u.s.Embassy/consulate general ] date of letter 15 th june

    and after received this letter i was received directly packet-3 at 22 th june from u.s.embassy/consulate general and i was fill this form and resend to us embassy. now i don’t know what is next step and us embassy does’t reply my answer by email and phon and we were not complete the case process at nvc because of that expedite process so please give me the answer of my question is thet what is my next step in this all situation please help me….

    • The case number was assigned by the National Visa Center on May 28, 2011. Based on the data I have primarily from 2009 and 2010, no interview was granted earlier than 56 days from the case number assignment date, which is July 23, 2011 for you. The first peak in the histogram above is around 190 days from the case number assignment date, which is December 4, 2011 for you. The end of the first peak is around 450 days from the case number assignment date, which is August 20, 2012 for you.

  3. hi
    can you help me please my mumbai consulate is put my case pending i section 221 but they required with me same documents which they required with me 1 st time its sponsor nd my sponsor is already more than 125 poverty guideline than why they are tor charing me i am already my husband suffering with kidney failuer problem and thats why we expedited our process and after 19 days my husbands surjeriy of kidney transplant and my consular know that about this problem but they putting my case pending again and again so ple help what i can do now?

  4. interview date

  5. Hi My category is f3.my father apply for me November 3 ,2009.its approved august 10 ,2010.My country is Bangladesh.How long i will wait for visa ?

  6. hi my sister filled f4 categaroy on 6th march 2003,file approve on 25th nov 2009 my bmb2009843048 when our file will process when we receive agent choice & biodata form.

  7. f 3 catagri priotiy date 23 august 2007 when it will be current

  8. my bmb no 2010767160

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