Pacific Behavioural Assessment

The Affinity Measure of Sexual Interest – Version 2.5

Affinity is a computer based ipsative assessment of sexual interest which combines two overt measures of sexual interest (designed to enable assessees to report the age and gender of sexual preferences in some detail) with a covert, ‘viewing time’ validity measure.

The first overt measure is a procedure by which simple prototype images are ranked. Crucially, each of the subsequent assessment images (which give rise to the rating and viewing time data) has been deemed an exemplar of a category represented by one of the prototypes. This was achieved by asking five judges to categorise many hundreds of images. Only those which all five judges agreed were representative of a prototype were included. The second overt measure is a procedure by which individual images are rated with respect to their sexual attractiveness.

The validity measure works by exploiting the well established finding that individuals spend longer gazing at images they find sexually attractive. It was established using the Affinity 1.0 prototype that these images did not need to be sexually explicit, or arousing in any way. It was also established that this phenomenon persisted (perhaps was even potentiated) when the assesee was actively engaged in rating the sexual interest of images. The latency of a rating can thus be used as a validity measure of the rating itself.

Software Facts

  • Affinity 2.5 is a simple and clear 20 minute assessment that includes a practice test and a scoring program.
  • The Affinity comes with a manual in PDF.
  • The Affinity’s results are open for clinician viewing. The raw viewing times, category scores, and the full report is available at any time to you.
  • You do not need to be connected to the internet to administer the test nor do you send the results anywhere.
  • The stimulus package consists of clothed images only, for a range of ages.
  • Version 2.5 is fully compatible with Windows XP, Windows Vista, Windows 7 or 8 and current Mac platforms.
  • This measure is appropriate for youth and adults.
  • Download the latest information on version 2.5 [PDF]
  • Download information on System Requirements (version 2.1 same as 2.5) [PDF]


  • We have multiple studies in progress evaluating Affinity 2.5 with both adolescents and adults. When available, we will provide updates.


  • US$1000 + US$40 handling fee for unlimited use and scoring reports for one licensed clinician.
  • US$175 for each additional user up to four additional users. For five or more users, purchased at the same time, the cost is $125.
  • Users can be updated at any time at no cost. This requires a new software key from Pacific Behavioural Assessment. The updated key is sent via email and instructions are provided to update the software. When a report is printed, the name of the licensed user is on the report, limiting unauthorized access.
  • In North America, Affinity 2.5 is available from Pacific Behavioural Assessment. Please contact us for more information.
  • In the UK and Europe, Affinity 2.5 is available for purchase from the developer Mr. David Glasgow. Please visit his website at

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Contact Us

D. Richard Laws, Ph.D.

David V. Glasgow, M. Clin. Psych.
Head, Product Development

Mail Address

PO Box 23032
Cook Street R.P.O.
Victoria, BC V8V 4Z8

Courier Address

101-230 Cook Street
ATTN: Post Office
Victoria, BC V8V 3X3

Fax: 250.388.5787