--> The most up-to-date data on time trials is maintained here.

 

---------

The information below is presented only for historical reasons.  These days (year 2018), a laptop running a 7th or 8th generation i5 or i7 processor would take less than a minute to process the examples tabled below.

 

The data minuted in the secs-y table below were obtained in October 2003, on a Pentium 4 running at 2 GHz. N is the number of data records in the Data worksheet; Nits is the number of items to be scored; Item scores indicates the amount of time to produce IStats' matrix of item scores; No eigens indicates the total time to completion, that is, time to create the item scores, the matrix of Pearson correlations, the matrix of tetrachoric correlations, and the DAT worksheet; With eigens indicates how much longer the job took when eigenvalues were also computed.

 

N

Nits

Item scores

No eigens

With eigens

450

40

13 secs.

27 secs.

51 secs.

1,400

25

24 secs.

33 secs.

42 secs.

2,800

25

48 secs.

1:02 mins.

1:11 mins.

5,600

25

1:45 mins.

2:12 mins.

2:21 mins.

11,200

25

4:04 mins.

4:51 mins.

5:08 mins.

 

Note December 2004: we received a trial data set from a Lertap user with N=267 and Nits=150.  It took Lertap a total of 14 minutes to produce its IStats report for this data set (!) -- of this, 11 minutes were required to extract eigenvalues from the correlation matrix.  This test used the same computer mentioned above, a Pentium 4 running at 2 GHz.  At the end of 2004, this Pentium would be considered as being quite dated (it was new in early 2002); if you're wanting IStats reports for data sets with large Nits, hopefully you'll have a more powerful computer to work on.

 

Note July 2010: fresh tests with another data set. This one had N=4,700 and Nits=77.  In this case, it took Lertap 3 minutes to produce its IStats report, a figure which includes the 43 seconds required to extract eigenvalues from the correlation matrix. We used Excel 2010 for this, running on a Macintosh MacBook Pro (2.53 GHz; 4 GB RAM) with Parallels and Windows 7 (if you have a more conventional Windows computer, not a Mac, you'd likely observe better figures).

 

Note December 2012: for a comparison of Excel 2010 and Excel 2013 running times, you might have a look at this document with a few selected time trials.