Functional capacity evaluations – my take on them!


Functional capacity evaluations

There are many forms of functional assessment available.  These range from a series of structured activities carried out in the home or work environment over a period of days or weeks to those that are carried out in a very precise manner in a clinic and often under the supervision of an occupational therapist or physiotherapist.  Both commercial (ie standardised and franchised) ‘Functional capacity evaluations’ (FCE) are available, as well as semi-structured or individualised assessments.

The term functional capacity evaluation has been criticised, because it can suggest that it is able to assess ‘capacity’ or ‘can do’, while most commentators believe that functional assessments can only assess what a person ‘will do’ (e.g. Battie & May, 2001).

One of the major criticisms of FCE is that few studies of reliability or validity have been published in peer reviewed journals.  This means most FCE have not been subject to the degree of scrutiny that is usually employed when developing assessment tools.  The relatively few studies that are available suggest that ‘only limited aspects of FCE reliability have been studied’ (Battie & May, 2001), and predictive validity, or the ability of the FCE to predict whether someone can or will return to work, is not strong (e.g. Gross, Battie & Cassidy, 2004)..

Reliability refers to whether two different people can conduct the FCE and obtain the same results (e.g. inter-rater reliability).  Intra- and interrater reliability for most FCE methodologies  have not been established.  There is some evidence that interrater reliability for establishing between ‘light’ and ‘heavy’ exertion, and whether a lift is performed safely, but mixed findings have been obtained for identifying the level that would ‘constitute safe, maximal lifting’ (Battie & May, 2001).  This means that when reviewing the findings of FCE, it is uncertain whether the same results would be achieved a second time, or by a different assessor.

Validity refers to whether an assessment is measuring the dimension it says it is measuring.  There are several different types of validity – content validity refers to whether the items used in the assessment ‘look like’ and agree with other ways of measuring a similar area – for example, do the items in the FCE measure the same sort of areas that disability questionnaires measure?  If they do, there should be a degree of similarity between the scores on both type of assessment if they’re completed by the same person.

Reneman et al. (2002) found little to moderate correlation between the self-report and performance-based measures, while Gouttebarge et al. (2009) found poor construct validity of lifting tests, discriminative validity was not statistically established, and convergent validity with self-reported pain intensity and disability was poor.

One of the most important aspects of validity is whether the results from an assessment can be used to predict behaviour in the ‘real world’ – this is predictive validity.  Gross and Battie (2005), found that FCE did not predict function at 12 months, and stated in a further paper that ‘The validity of Functional Capacity Evaluation’s purported ability to identify claimants who are “safe” to return to work is suspect.’ (Gross, Battie & Cassidy, 2004).  A very recent study demonstrated that while FCE was related to return to work the predictive efficiency is poor, with the findings contributing only 5% to the overall model (Striebelt, et al.2009).

Strong and colleagues provide recommendations as to how FCEs should be requested, undertaken, reported and particularly applied to reduce work disability among injured workers and this paper, in part, describes my approach with clients when discussing the relevance and limitations of FCE results (Strong et al. 2004).

FCE can provide some helpful information to both client and health provider when used as a ‘pre and post’ assessment, to monitor functional improvement, and to assist a client to develop an awareness of the areas of functional performance he or she may need to improve on (such as improving grip strength, manual handling technique or cardiovascular fitness).  At the same time, FCE is a measure of volitional behaviour at one time in a clinical setting, as opposed to a ‘real world’ setting where consistent performance is necessary.  As I have indicated above, the predictive validity of FCE is not strong, and FCE should not be relied upon to determine ability to carry out activities over the course of a day or week.

Gouttebarge, V., Wind, H., Kuijer, P. P., Sluiter, J. K., Frings-Dresen, M. H., Gouttebarge, V., et al. (2009). Construct validity of functional capacity evaluation lifting tests in construction workers on sick leave as a result of musculoskeletal disorders. Archives of Physical Medicine & Rehabilitation, 90(2), 302-308.

Gross, D. P., & Battie, M. C. (2006). Functional Capacity Evaluation Performance Does Not Predict Sustained Return to Work in Claimants With Chronic Back Pain. Journal of Occupational Rehabilitation, 15(3), 285-294.

Gross, D., Battie, M., & Cassidy, J. (2004). The prognostic value of functional capacity evaluation in patients with chronic low back pain: part 1: timely return to work. Spine, 29(8), 914-919.

Gross, D. P., Battie, M. C., Gross, D. P., & Battie, M. C. (2004). The prognostic value of functional capacity evaluation in patients with chronic low back pain: part 2: sustained recovery Spine, 29(8), 920-924.

Reneman, M. F., Jorritsma, W., Schellekens, J. M., & Goeken, L. N. (2002). Concurrent validity of questionnaire and performance-based disability measurements in patients with chronic nonspecific low back pain. Journal of Occupational Rehabilitation Vol 12(3) Sep 2002, 119-129.

Soer, R., Groothoff, J. W., Geertzen, J. H. B., Cp, Reesink, D. D., & Reneman, M. F. (2008). Pain response of healthy workers following a functional capacity evaluation and implications for clinical interpretation. Journal of Occupational Rehabilitation, 18(3), 290-298.

Streibelt, M., Blume, C., Thren, K., Reneman, M. F., & Mueller-Fahrnow, W. (2009). Value of functional capacity evaluation information in a clinical setting for predicting return to work. Archives of Physical Medicine & Rehabilitation, 90(3), 429-434.

Strong, S., Baptiste, S., Clarke, J., Cole, D., & Costa, M. (2004). Use of functional capacity evaluations in workplaces and the compensation system: A report on workers’ and report users’ perceptions. Work, 23(1), 67-77.

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5 comments

  1. Reliability and prediction will never be strong with FCE but this is not because of the FCE process or the evaluator. Much stronger are the variable factors – the patients motivation to co-operate plus the environmental and social factors that affect their perception of ability and disability.
    A patient who is motivated to get back to work (and has work to return to) can be expected to give good effort and reasonably consistent results, no matter who the evaluator is or how many times a particular test will be administered. A patient who had a boring job, has no job to return to and has adapted comfortably to a lifestyle of not working is unlikely to give good effort if (s)he perceives that being certified fit for work only means loss of compensation income.
    Remember too that the FCE was originally developed because of the inability of doctors to reliably certify work ability and then to justify that certification on any clinical reasoning.
    The FCE may not be perfect but at least we do get to observe how the patient actually attempts work-related tasks rather try to guess what they are capable on based on impairment and symptoms and patient statement.

    1. Functional performance has, as you point out, many variables influencing it. While undoubtedly some people are inclined to reduce their effort because of lack of “motivation” to return to work, this is not the only reason for poor functional results. The problems with FCE is, as I’ve pointed out in other media, that results are over-interpreted, they are often viewed as valid predictors of performance in the workplace, and when results are provided without reference to peer-reviewed literature for normative data or for the validity of measures of “effort” or “consistency”, one has to question their usefulness.

      FCE doesn’t have an established predictive validity, yet the results are promulgated within reports, and by purchasers of those reports, as valid predictors of work performance. To my mind this makes FCE perhaps a reliable test, but nonetheless an invalid test. Add to this, the literature suggesting that operators conducting FCE differ in the way they carry out testing, and we have an unreliable test that is also invalid.

      While I don’t have a suggestion for ways to predict function without asking a person to do what they do in a realworld situation, I don’t think FCE, as used by so many, and promoted by so many, is a helpful method. It doesn’t appear to provide what it purports to provide, and that is a reliable and valid way of establishing “work capacity”.

      Again, as I’ve pointed out in other media, FCE has some benefits – and you’ve identified one of them, that an individual actually does functional movements and is observed doing so. This is better than “educated guessing” carried out by doctors simply asking the person what they can do. I also think that people with chronic pain benefit from testing their own abilities by doing activities with a supportive coach helping them – and deciding, on biomechanical and kinesiophysical grounds, what is and isn’t safe. This is a far cry from the FCE reports I’ve read in which people are identified as showing “poor effort”, “inconsistent results”, and in which predictions about work capacity are made.

      Wouldn’t it be far more useful to work alongside individuals, establish what their fears about returning to work are, and systematically work through these obstacles, including appropriate use of legislation for the small number of people who are “comfortable” with their lifestyle?

      BTW the research I’ve carried out on motivation for return to work suggests that few people indicate that working is of low importance, with most placing it above 80mm on a 0 – 100mm VAS where the anchors are 0 = not at all important and 100 = extremely important. What is striking is the very low level of confidence that people have for returning to work – most below 30mm on the same VAS where 0 = not at all confident and 100 = completely confident.

      I guess if I was to think that I might not be able to carry out a full day’s work to the standard I believe an employer wants, and that I would have increased pain such that I wouldn’t be able to sleep, and I had few coping strategies, and my job skills were limited, and I’ve never looked for work more than once or twice, I might be similarly lacking in confidence. And I might not push myself in a functional test that would be used to accuse me of lacking effort but quite capable of working, and would leave me with a flare-up that wouldn’t settle for days.

      FCE is a blunt instrument when used the way I’ve seen it used, and when written in a way that suggests it can do more than the literature suggests it can. My report card on FCE? Needs more work IMHO.

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