Introduction

You submit an OCF-18 for psychological treatment. The insurer sends the claimant to a section 44 examination. The insurer's assessor administers the Structured Inventory of Malingered Symptomatology. Your assessor used the Beck Depression Inventory, the Beck Anxiety Inventory, and the Impact of Events Scale. Zero validity testing.

The Tribunal prefers the insurer's report. Your treatment plan is denied. The claimant stays in the Minor Injury Guideline.

This is not a hypothetical. It is the outcome in 9 of the top 10 LAT decisions from 2018 to 2026 where validity testing was an issue. The pattern is unusually consistent: assessments that include standalone symptom validity tests are systematically preferred over assessments that rely exclusively on self-report inventories. The SIMS, in particular, has become the instrument the Tribunal expects to see.

The lesson for psychological assessors and the clinics that bill for their work is straightforward. If your assessment battery does not include at least one validated symptom validity test, the other side's will. And the LAT has shown, repeatedly, that it will choose the assessment with validity data.

The SIMS Gap: How the Tribunal Chooses Between Competing Assessments

Across 10 LAT decisions where the SIMS appeared, a binary pattern emerges. One assessor administered validity testing. The other did not. The Tribunal preferred the assessment with validity data in 9 of 10 cases.

The cases span eight years and multiple adjudicators, but the reasoning is nearly identical each time. In 2025 CanLII 75765 (ON LAT), the applicant's assessor used six self-report measures with no validity testing. The insurer's assessor administered the SIMS and found a score of 27 -- nearly double the malingering cutoff of 14. The Tribunal found psychological impairment not established.

In 2020 CanLII 34436 (ON LAT), the insurer's assessor administered both the TSI-2-A and the SIMS. Both flagged over-endorsement. The applicant's assessor did no validity testing at all. The Tribunal's reasoning was explicit: "The difference between the two reports was that [the insurer's assessor] conducted additional validity testing that [the applicant's assessor] did not." The IE was preferred.

In 2022 CanLII 45256 (ON LAT), the applicant failed validity testing across two separate insurer examinations. The first insurer examiner found the SIMS significantly elevated, the Pain Patient Profile invalid, and the TSI-A profile invalid. The second insurer examiner, a year later, found inadequate effort on the Rey Memory Test, continued SIMS over-reporting, and pain scores above 97.3% of the normative sample. The applicant's own assessor reviewed the first insurer report and knew about the validity concerns but did no further testing beyond the Rey 15-Item Test. The Tribunal's conclusion was not that the applicant's symptoms were mild. It was that the data was too contaminated to determine whether any diagnosis applied at all.

The one exception -- 2023 CanLII 44310 (ON LAT) -- is instructive in the opposite direction. The SIMS showed no sign of symptom magnification. This finding helped validate the applicant's presentation. The SIMS is not an insurer weapon. It is a neutral tool that can help either side.

The 2026 decisions confirm the pattern is alive and well. In 2026 CanLII 34355 (ON LAT), the Tribunal gave little weight to a report built on what it called "subjective psychometric testing that does not offer any validity testing to confirm the accuracy or the proportionality of the applicant's self report." The Tribunal has developed a shorthand for this gap. In [2026 CanLII 68558 (ON LAT)], the insurer's examiner calculated a 67 percent probability that the symptom validity results were invalid and concluded flatly: "There is no psychological diagnosis as the test results were deemed invalid."

The Domino Effect: When Validity Fails, Everything Fails

Once the SIMS or another validity measure flags symptom exaggeration, the LAT does not compartmentalize. It treats all self-report data as potentially contaminated. This is most explicit in 2019 CanLII 22210 (ON LAT), where the Tribunal stated there was "reason to believe that the self-report based testing (e.g. BAI, BPI, etc.) relied on by [the applicant's assessor] likely was affected by a tendency to magnify."

The chain of reasoning runs through every decision:

1. The validity test flags over-endorsement or atypical responding 2. The Tribunal concludes that self-report data cannot be trusted 3. Without trustworthy data, a DSM-5 diagnosis cannot be made 4. Without a DSM-5 diagnosis, the claimant stays in the MIG

This is the fundamental risk of submitting an assessment without validity testing. Your entire report -- not just the parts the IE's SIMS contradicts -- is vulnerable. The Tribunal will not assume honest responding. It will look for evidence that you checked.

For providers submitting treatment plans, this connects directly to the billing consequences covered in our roundup of 2026 LAT decisions affecting HCAI invoicing. A denied psychological treatment plan is often a $2,500 to $4,000 loss. The cost of administering a SIMS is 10 to 15 minutes. The math is not close.

The Second Axis: The Diagnosis Has to Match the Scores

Validity testing is necessary but not sufficient. A second failure pattern runs through the 2024--2026 decisions: assessments where the diagnosis is not traceable to the test scores.

In 2024 CanLII 97882 (ON LAT), two psychologists faced off over chronic pain. The adjudicator could not find "where in the assessment [the competing assessor] tested the applicant to diagnose chronic pain," and found the diagnosis "seems to conflict with the results of the interview portion and the psychometric testing." The other psychologist, by contrast, "outlined a clear connection between his psychometric testing and his diagnosis" -- and was preferred. It is not enough to administer tests. The report must show the line from scores to diagnosis.

The same defect recurs:

  • In 2024 CanLII 94152 (ON LAT), the adjudicator was "not directed to how the doctor rendered the diagnosis based on the self-report and psychometric testing."
  • In 2026 CanLII 21056 (ON LAT), the insurer won by citing A.R. v. Coseco (2020 CanLII 30389), where psychometric results that did not align with the diagnosis were given little weight.
  • In 2025 CanLII 94802 (ON LAT), the adjudicator was not persuaded by the psychometric results because they were inconsistent with the applicant's presentation at the interview.
  • In 2023 CanLII 2707 (ON LAT), testing that produced scores "much higher than even in-patient psychiatric populations" became an exaggeration flag.

There is a third axis too: authorship. In 2026 CanLII 29569 (ON LAT), the claimant's section 25 report actually corroborated the insurer's psychometric results -- and still lost, because it was prepared under supervision without a records review or firsthand observation. In 2026 CanLII 12716 (ON LAT), a psychologist who diagnosed from a social worker's notes and test administration was weighed against an assessor with direct observations. Valid data collected by someone else, without the author in the room, does not carry the same weight.

The Recurring IE Assessors: Know What You Are Up Against

Several names appear repeatedly across these decisions as the insurer's assessor of choice. Their standard batteries draw from a predictable set of instruments:

  • Validity testing: SIMS, TOMM, SIRS-2, Rey-15
  • Trauma and personality: TSI-2-A, PAI (both with embedded validity scales)
  • Mood and anxiety: BDI-II, BAI, CAD
  • Functional and pain: Brief Pain Inventory, WHODAS 2.0
  • Additional screening: PCL-5, P3

If you submit an assessment with BDI-II, BAI, and BHS against the insurer's TSI-2-A plus SIMS battery, you are walking into a known asymmetry. The Tribunal will notice the gap. The cases show it notices every time.

The TSI-2-A plus SIMS combination is particularly effective because it provides two layers of validity data. The TSI-2-A has embedded validity scales measuring over-endorsement. The SIMS provides standalone multi-domain screening across five domains: psychosis, neurologic impairment, affective disorders, amnestic disorders, and low intelligence. Together, they match what the Tribunal has consistently found persuasive.

The Rey 15-Item Trap

Several applicant assessors in these decisions used the Rey 15-Item Test as their only validity measure. In every case, it was not enough.

The Rey is a 1960s memory screen repurposed as an effort measure. It tests one domain -- memory effort -- with 15 items. It has low sensitivity and is easy to identify as a "malingering test." The SIMS, by contrast, is a 75-item questionnaire covering five symptom domains, appears as a genuine symptom inventory, and was designed and normed specifically as a symptom validity test.

The 2022 CanLII 45256 (ON LAT) decision is the definitive cautionary tale. The applicant's assessor administered the Rey 15-Item and reported it "detected no exaggeration of memory difficulties." The applicant passed. Then the insurer's assessor administered a more rigorous version and found inadequate effort. Four additional validity measures all flagged significant exaggeration. The applicant failed eight validity tests across two IEs. The Rey gave a false negative while every modern instrument caught the problem.

The Tribunal's response was pointed: the applicant's assessors knew about the earlier validity concerns and "provided no explanation on why they did not conduct any further validity testing, other than the Rey-15 Item Test."

Using the Rey 15-Item as your sole validity measure is barely better than using none at all. A proper battery needs at least one modern, multi-domain symptom validity test -- SIMS, TOMM, or M-FAST -- or an omnibus instrument with embedded validity scales like the PAI or TSI-2-A.

The 2024 case of 2024 CanLII 28815 (ON LAT) adds a second trap: the wrong validity measure. The only test addressing validity in the competing report was a Rey 15-Item, described as measuring "the possible amplification of memory deficits" -- in a file where memory deficits were never at issue. An effort measure aimed at the wrong domain is as weak as none. The mirror problem is an unexplained battery: in 2021 CanLII 111151 (ON LAT), an assessor who administered only the BBHI-2, P-3 and TOMM was criticized because "no rationale was provided for the choice of psychometric tests."

This documentation standard mirrors what we have seen across billing disputes at the LAT in 2026: specificity and thoroughness win. Shortcuts lose. The same principle that applies to brokerage fee logs and attendant care documentation applies to psychological assessment batteries.

A framework every provider should internalize:

Validity testing, even when clean. The insurer's assessor had validity data and the applicant's assessor did not. The Tribunal noted that the applicant's assessor diagnosed "primarily on the basis of the applicant's reported symptoms and self-report measures" -- a statement that reads as criticism in the LAT context.

Medical record reconciliation. The insurer's assessor reviewed the family doctor's records and noted the complete absence of psychological complaints. The applicant's assessor diagnosed Major Depressive Disorder without reconciling the silent medical record.

Objective test anchoring. Normal-range CAD, TSI-2-A, and BAI scores were consistent with both the clinical presentation and the medical record. The elevated scores in the applicant's assessment came from instruments with no validity checks.

The framework in 2026 CanLII 77484 (ON LAT) matters because it shows what a defensible assessment looks like from both sides. A valid SIMS result means your other test scores can be interpreted with confidence. That validity data, combined with medical record review and objective test anchoring, is what the Tribunal found persuasive.

For clinic directors managing assessment referrals, the same principles that apply to justifying rates above the Professional Services Guideline apply here: evidence wins. An assessment without validity testing is like a rate dispute without market data. You might get lucky, but the pattern says you will not.

When Psychometrics Win -- and Where the Rule Bends

The pattern also has a positive side, and its limits matter for honest counsel.

The cleanest claimant win in the recent record is 2022 CanLII 120024 (ON LAT). The applicant's assessor administered the BDI-2 (moderate depression), BAI (severe anxiety) and the Pain Patient Profile. The insurer's assessor independently produced the same finding. The adjudicator placed "great weight on the fact that both the applicant's and the respondent's psychological assessors conducted psychometric testing which yielded results of moderate depression" -- and removed the applicant from the MIG, with the assessment payable plus interest. Convergence between both sides' testing is the strongest position a claimant can be in. In 2018 CanLII 2305 (ON LAT), the adjudicator put the principle plainly: "The inclusion of psychometric tests produces a more sustained analysis."

But the rule is one of weight, not law. Three decisions set its boundaries:

  • In 2026 CanLII 64882 (ON LAT), the Tribunal accepted a psychiatrist's clinical diagnosis without extra psychometric testing, noting she was "trained to diagnose and assess and treat psychiatric disorders without the use of psychometric testing."
  • In 2019 CanLII 72223 (ON LAT), a reconsideration was dismissed where the Tribunal had preferred an applicant psychologist using self-report measures without major validity indexes -- weighting, not an automatic rule.
  • In the 2026 McKillop Mutual decision, failed validity testing during one assessment did not defeat the treatment plans, because the insurer's argument did not carry the weight of the rest of the record.

Validity testing is the evidence the Tribunal reaches for first. It is not a magic wand for either side.

For Clinic Directors and Billing Administrators

Ask your assessing psychologist what validity tests they include. If the answer is "none," your OCF-18 for psychological treatment is vulnerable before the patient is assessed.

Review assessment reports for the "SIMS gap" before submitting to the insurer. If the report does not mention validity testing, ask for a supplement. It is easier to fix before the insurer's IE is on file.

The cost of adding a SIMS is negligible compared to the cost of a denied assessment. The numbers appear in the decisions themselves: a $2,494.54 psychometric testing plan (2021 CanLII 314), a $4,400 neuropsychological assessment and psychometric testing plan denied outright (2023 CanLII 116466), and a $2,000 assessment cap under s. 25(5)(a) of the Schedule that psychometric testing cannot be unbundled to bypass. A plan denied because the assessment lacked validity testing is a poor trade for 15 minutes and a $10 form. The same logic applies to every line item on an OCF-18 -- see Admin Time Is Not Treatment Time: the time invested in getting the details right pays for itself the first time a treatment plan survives scrutiny.

Conclusion

The LAT case law on psychological assessments is unusually consistent. From 2018 to 2026, the message has not changed: validity testing separates credible assessments from those the Tribunal will set aside. The SIMS is the most frequently cited instrument, but the principle is broader. The Tribunal wants to know that the data underlying a diagnosis has been tested for reliability.

For psychological assessors, the strategic question is simple: do you want your assessment compared without validity testing of your own? If the answer is no, the SIMS -- or an equivalent -- belongs in every MVA psychological assessment battery you submit.

An assessment that includes validity testing, reviews the medical record, and anchors conclusions in objective data is not just more defensible at the LAT. It is the standard of care. Adopt it before the other side does.