O’Connor Finger and Tweezer Dexterity Tests



The O’Connor Dexterity Battery by O’Connor (1926) is a standardized assessment of hand-eye coordination as well as fine motor control and consists of activities involving a finger test and a tweezer test. In both, the client is asked to place pins into a single hole on a board using only his or her fingers or by using a set of tweezers. The equipment for each subtest is separate, so the battery includes two separate boards. The main differences between the boards is the diameter of the hole and its ability to accommodate 1 or 3 pins at a time. Both boards consist of 100 holes arranged in 10 rows of 10 holes each spaced 0.5 inch apart. Above the holes at the top of the board is a well that holds the metal pins residing in a tray whose cover slides open and closed. Each pin is 1-inch long and 1/16 of an inch in diameter (Kirby, 1979). During the finger test, the subject is required to pick up and place 3 pins in 1 hole (x 100) on the board, thus the diameter of the holes can accommodate 3 pins at roughly 3/16 of an inch; whereas the tweezer test requires only 1 pin to be picked up at a time with tweezers and placed into each of the 100 holes that are roughly 1/16 of an inch. The time required, in seconds, to fill the 100 holes is the basis for the score for both batteries. Administration time is less than 20 minutes for each.


Original test-retest reliability scores for the finger test were r= 0.60 however, the research was completed under employment conditions which may account for low correlative scores where the fastest speed for both men and woman was 5.70 minutes with a median of 7.70 minutes (Hines & O’Connor, 1926). A later article by Fleishman (1953) noted studies by Darley (1934) and Blum (1940) that showed test-retest reliabilities to be r = 0.90 and 0.89, respectively; whereas Fleishman’s own work produced test-retest reliabilities ranging from 0.71 to 0.86 under various conditions such as time constraint and work limit (i.e., using full and half boards). A subsequent factor analysis determined that the O’Connor Finger Test was most heavily loaded on manual dexterity (0.62), followed by finger dexterity (0.28), visual acuity (–0.09), then depth perception (0.05); whereas factor analysis of the Tweezer test was 0.46 for manual dexterity, followed by finger dexterity (0.04), tweezer dexterity (0.32), and visual acuity (–0.23) (Bourassa & Guion, 1959). Candee and Blum (1937) were able to stratify people using the finger test into superior workers with a mean score of 6.55 (range 5.56 to 8.06) and mediocre workers with a mean score of 7.32 (range 5.57 to 9.49). Lundergan, Soderstrom, and Chambers (2007) found that median scores of a dental student cohort for the Tweezer test using slightly different scoring parameters was men = 327 and women = 323, which was significantly better than published norms of men = 360 and women = 342.20. The same study found that the Tweezer test also significantly correlated with the Perceptual Ability Test at r = 0.24 and concluded that the original O’Connor Tweezer Test was a weak predictor of grades in dental school when compared with the modified O’Connor Tweezer Dexterity Test #18 which requires pins to be removed from holes and placed in holes requiring more speed and accuracy than the original.


The Tweezer Dexterity Test itself is an original concept and there are few performance measures that assess the same complex fine motor control sought after in the Tweezer Test. Both the Finger and Tweezer Test have been in use since the 1920s and there are a number of studies with age-referenced norms available. The assessments require no special training or certifications and can be administered inn less than 20 minutes.


Fleishman (1953) argues that relative to other dexterity tests (i.e., Minnesota Rate of Manipulation and Purdue Pegboard), the test takes considerably longer to administer at a typical range of 8 to 15 minutes. Also, the test yields only one score, whereas the Purdue Pegboard Test, for example, can yield five scores (right, left, both hands, total of those, and assembly), and the Minnesota Rate of Manipulation Test yields at least two scores (placing and turning). Additionally, the amount of current research pertaining to the batteries is limited.


Detailed instructions are included in the examiner’s manual as well as standardized norms and percentile ranks of each assessment when purchased. During assessment the clinician uses specific prompts, whereby the subject is asked to take pins from the shallow bowl at the top of each board and place them into specific grooved holes that accept the pins on the board. The Finger Test requires the placement of 3 pins into 1 hole and the tweezer test requires 1 pin in 1 hole using only tweezers. Scoring is based on how fast the person can complete the assigned task of filling the 100 holes on the board. Errors and misplaced pins are accounted for during scoring, which is usually in minutes/seconds. Scoring for each assessment requires unique algorithms. For example, the finger test requires the following computation:



The O’Connor Dexterity Tests can be purchased from various therapy supply companies and cost varies from $125 to $175 each. To use in research or publication contact where purchased or where published. More information about the battery can be found in the following original journal articles:

Hines M., & O’Connor J. (1926). A measure of finger dexterity. Journal of Personnel Research, 4, 379-382.

Fleishman, E. A. (1953). A modified administration procedure for the O’Connor Finger Dexterity Test. Journal of Applied Psychology, 37(3), 191-194.


POPULATION Suspected hand/finger injury; work rehabilitation; general
TYPE OF MEASURE Activity-based functional performance
WHAT IT ASSESSES Fine motor; hand dexterity; visual component
TIME < 20 minutes
COST $125 to $175


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Jul 27, 2017 | Posted by in MEDICAL ASSISSTANT | Comments Off on O’Connor Finger and Tweezer Dexterity Tests

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