Interesting to hear about the use of the SWOT analysis in HR Management. I have always used it for business-strategy decisions (e.g., shall we implement this new product/technology in the future?).

I saw you used the word "interpret". You want to use the SWOT analysis to interpret an employment act.

To me the SWOT analysis is a tool that can help decision makers navigate future decisions rather than interpreting something happening in the past.

I invite other researchers to question my view. 

You might need to look at the SWOT analysis for different groups of people affected bob the Employment act e.g. Employers and Employees and see how they compare

Something in the act which is a "strength" for the employee (for example - guaranteed redundancy payments or maternity leave conditions) might be judged as a "threat" for the employer due to the increased costs involved in implementing them

...equally you might think they're a "strength" for the employer too - better protected workforce might be more productive for example.

To make it effective, you might have to start by laying out the criteria by which you'll decide where something falls on the SWOT, e.g. purely economic benefit, or caring for people, or company stability or....

I am not sure I understand the question.  Are you advocating that HR managers use a structured SWOT analysis before making a hiring decision, or that they do in fact do a SWOT when evaluating candidates?

As a hiring manager in both small and large companies who has hired in both technical and sales areas, I would say that focus is principally on the S, W and T.  O is not a principal consideration except in early career hires where you are taking on a substantial mentoring and training component for that person.  For example, hiring for an executive training program or other entry level jobs with a ladder of achievement expected and built in, you focus on the potential of the candidate to grow.  S is about "can this person do the job" and "will the person fit in the culture".  W is about "what skills haven't they demonstrated in the past" and are there "gaps in interpersonal skills".  T is all about "are there red flags that indicate a likelihood of failure".

The decision making is not done on paper in quadrants like a SWOT, but that is what is going through my head when I am evaluating a candidate.  Furthermore, you need to look at hiring as a process: screening (increasingly done using automation) -> interviews -> reference checks -> background checks -> hire -> probation -> permanent hire.  There is not one decision, but a sequence of decision points that should be evaluated independently.  It really is a decision tree.  

I ultimately make most of my decisions about hiring at the interview stage and rely on subjective intuition (that is then justified with concrete reasons for hire/not hire for legal cover).  Evaluating technical people, it is about skill set and cultural fit.  Engineering is a collaborative enterprise and you need to make sure the new hire will fit with culture (unless you are looking to hire a change agent to disrupt a bad culture).  I also do not focus on formal qualifications.  One of my best guys, had only graduated high school, had long hair and a beard, wore nothing that wasn't leather or denim, but he was a rock star C programmer, whose performance had been demonstrated by contributions to open source.

With salespeople, it comes down to "if I were a buyer, would I trust this person?" and "are they are hunter or a gatherer?" which depending on the type of position, you want one type or another.  A key indicator for me is motivation.  Sales is a very difficult job, because as a salesperson you deal with rejection most of the time.  It is a reason why narcissists do well in sales, they can shrug off rejection.  I cull candidates that view sales as zero-sum (I win by taking the customer's money and the customer loses by spending the money), and go with candidates that view sales as positive sum (Pareto efficient: I win by taking your money and you win by solving your problem).  

In the past, I worked at a firm that did complex solution selling (c.f., Miller Heiman structured sales) that had long sales cycles.  A sales person that needed constant validation with numerous quick transaction successes would not perform well in that environment.  (In the industry they are known as "box pushers".)  On the other hand, people who have the skills and temperament to do consultative selling can cross product categories.  Even though they had never sold enterprise security software before, the best performers were two salespeople who previously sold billion dollar power plants to power companies.  They were comfortable with long sales cycles and consultative selling.

You may want to approach the research from an empirical standpoint with a well constructed questionnaire on hiring decisions, or perhaps find an existing data set and place it in a SWOT context.  Beware that you will be working with a voluntary response sample and not a random sample and treat statistical measures appropriately.

Good luck.