Neck pain is a common problem in our society, accounting for 20% of all chiropractic visits. Physical therapy interventions for chronic neck pain have been chosen based on the patient's symptoms and examination findings. These interventions include superficial and deep heat, massage, traction, manual therapy, and exercise programs. There is little controlled research addressing the efficacy of these therapies. Although many of these interventions provide some patients with pain relief and increased function, studies often utilize multiple interventions on the same subject such as heat, ultrasound, cervical traction, range of motion exercises, making interpretation of the results difficult. Much of the literature to date has focused on studies of subjects suffering from acute neck pain. Many of these studies suggest that subjects report decreased pain, decreased disability and increased cervical spine active range of motion. There are no controlled studies comparing the effects of spinal mobilization and standard physical therapy on subjects with chronic neck pain. The object of this study is two fold: 1) to determine the score variability of two neck disability questionnaires )both baseline and change scores) to be used in sample size calculations, and 2) to establish the ability to recruit, treat and follow sufficient numbers of subjects needed for a full clinical trial. The ability to predict outcomes of neck pain treatment will lead to more appropriate therapies and an avoidance of unnecessary treatments.