measurement of the outcome is critical for any decision - making and results of evaluations in all medical circumstances . the japan orthopaedic association ( joa ) developed and published a specific instrument to measure outcomes for patients with low back problems in 1986.1 it was called the joa score rating system for low back pain , with a full score being 29 points . since then , the instrument has been widely utilized to evaluate the functional results of many types of intervention for patients with such problems . it has been referred to not only in articles by japanese investigators2 but also in those by non- japanese - speaking investigators.3,4 one of the major criticisms of this specific instrument , however , is that it is not a patient - oriented measurement but a physician - based one . it is now widely accepted that a patient s perspective is essential for making medical decisions and for evaluating the results of interventions.5 based on the current needs for measuring outcome , the joa was urged to revise its original score rating system and to develop a new one . in 2002 , a subcommittee on evaluation of back pain and cervical myelopathy was organized in the clinical outcome committee of joa , and work began on revising the original joa scoring system . as described in the previous literature concerning part 1 , the original joa scoring system was revised and a new scoring system ( the joa back pain evaluation questionnaire  joabpeq ) was developed.6 the key points of this revision were to make the original joa score more patient - oriented . for the survey in the part 1 study , we first created a preliminary questionnaire consisting of 60 items . the questionnaire was a self - administered , disease - specific measure that was created with reference to the japanese editions of the short form health survey with 36 questions ( sf-36)7 and the roland - morris disability questionnaire ( rdq)8 to assess health - related quality of life . from the survey , a total of 25 items were selected for tentative use on a draft of the joabpeq ( table 1 ) . table 1items ( n = 25 ) selected for the draft of the joabpeq evaluated in this studywith regard to your health condition during the last week , please circle the item number of the answer for the following questions that best applies . if your condition varies depending on the day or time , circle the item number when your condition is at its worst.q1 - 1 . to alleviate low back pain because of low back pain , you do not do any routine housework these days.1 ) no2 ) yesq1 - 3 . because of low back pain , you lie down more often than usual.1 ) yes2 ) noq1 - 4 . because of low back pain , you sometimes ask someone to help you when you do something.1 ) yes2 ) noq1 - 5 . because of low back pain , you refrain from bending forward or kneeling down.1 ) yes2 ) noq1 - 6 . because of low back pain , you have diffi culty standing up from a chair.1 ) yes2 ) noq1 - 7 . your lower back aches most of the time.1 ) yes2 ) noq1 - 8 . because of low back pain , turning over in bed is diffi cult.1 ) because of low back pain , you have diffi culty putting on socks or stockings.1 ) yes2 ) noq1 - 10 . because of low back pain , you walk only short distances.1 ) yes2 ) noq1 - 11 . because of low back pain , you stay seated most of the day.1 ) yes2 ) noq1 - 13 . because of low back pain , you become irritated or angry at other persons more often than usual.1 ) yes2 ) noq1 - 14 . because of low back pain , you go up stairs more slowly than usual.1 ) yes2 ) noq2 - 1 . how is your present health condition?1 ) excellent2 ) very good3 ) good4 ) fair5 ) poorq2 - 2 . do you have diffi culty in climbing stairs?1 ) i have great diffi culty.2 ) i have some diffi culty.3 ) i have no diffi culty.q2 - 3 . do you have diffi culty in any one of the following motions : bending forward , kneeling , or stooping?1 ) i have great diffi culty.2 ) i have some diffi culty.3 ) i have no diffi culty.q2 - 4 . do you have diffi culty walking more than 15 minutes?1 ) i have great diffi culty.2 ) i have some diffi culty.3 ) i have no diffi culty.q2 - 5 . have you been unable to do your work or ordinary activities as well as you would like?1 ) i have not been able to do them at all.2 ) i have been unable to do them most of the time.3 ) i have sometimes been unable to do them.4 ) i have been able to do them most of the time.5 ) i have always been able to do them.q2 - 6 . has your work routine been hindered because of the pain?1 ) greatly2 ) moderately3 ) slightly ( somewhat)4 ) little ( minimally)5 ) not at allq2 - 7 . have you been discouraged or depressed?1 ) always2 ) frequently3 ) sometimes4 ) rarely5 ) neverq2 - 8 . do you feel exhausted?1 ) always2 ) frequently3 ) sometimes4 ) rarely5 ) neverq2 - 9 . do you feel happy?1 ) always2 ) almost always3 ) sometimes4 ) rarely5 ) neverq2 - 10 . do you think you are in reasonable health?1 ) yes ( i am healthy.)2 ) fairly ( my health is better than average)3 ) not ( very much)/particularly ( my health is average)4 ) barely ( my health is poor)5 ) not at all ( my health is very poor)q2 - 11 . do you feel your health will get worse?1 ) very much so2 ) a little at a time3 ) sometimes yes and sometimes no4 ) not very much5 ) not at all items ( n = 25 ) selected for the draft of the joabpeq evaluated in this study the purpose of the part 2 study in this project was to evaluate the reliability of the 25 items selected for the draft joabpeq ; for this , test - retest reliability was ascertained . altogether , 460 of the 829 japanese board - certified spine surgeons were randomly selected , and each was asked to recruit two patients to evaluate the joabpeq between january and june 2004 . the recruited patients were scheduled to reply to the questionnaire twice at a 2-week interval . patient criteria were as follows : ( 1 ) patients could be any age of either sex ; ( 2 ) patients had any lumbar spine disorder and were currently visiting an outpatient clinic ; ( 3 ) the severity of the symptoms was expected to be at the same level between the two interviews . exclusion criteria were the presence of : ( 1 ) other musculoskeletal diseases requiring medical treatment ; ( 2 ) psychiatric disease ( e.g. , dementia ) , potentially leading to inappropriate answers ; ( 3 ) a postoperative condition ; ( 4 ) having participated in previous surveys of the related study . each patient was asked to complete the same questionnaire twice at an interval of 2 weeks ( 3 days ) . the attending surgeon filled out the patient information on the diagnosis and the presence or absence of concomitant diseases , followed by judging the severity of symptoms using a three - step rating scale ( mild , moderate , severe ) . symptom severity was determined subjectively by the attending surgeon , who was asked not to select a similar patient solely on the basis of severity . patients who had the same level of severity as judged by all surgeons were then selected and analyzed to verify the reliability of the questionnaire . this study was approved by the ethics committee of the japanese society for spine surgery and related research . the reliability of the questionnaire was evaluated by determining the extension of the kappa coefficients . the kappa and weighted kappa coefficients were calculated based on a formula using microsoft office excel 2003 . kappa and weighted kappa coefficients of 0.4 or above were judged to be reliable.9 the 95% confidence intervals ( 95% ci ) were calculated for all reliability coefficients using the bootstrap method . altogether , 460 of the 829 japanese board - certified spine surgeons were randomly selected , and each was asked to recruit two patients to evaluate the joabpeq between january and june 2004 . the recruited patients were scheduled to reply to the questionnaire twice at a 2-week interval . patient criteria were as follows : ( 1 ) patients could be any age of either sex ; ( 2 ) patients had any lumbar spine disorder and were currently visiting an outpatient clinic ; ( 3 ) the severity of the symptoms was expected to be at the same level between the two interviews . exclusion criteria were the presence of : ( 1 ) other musculoskeletal diseases requiring medical treatment ; ( 2 ) psychiatric disease ( e.g. , dementia ) , potentially leading to inappropriate answers ; ( 3 ) a postoperative condition ; ( 4 ) having participated in previous surveys of the related study . each patient was asked to complete the same questionnaire twice at an interval of 2 weeks ( 3 days ) . the attending surgeon filled out the patient information on the diagnosis and the presence or absence of concomitant diseases , followed by judging the severity of symptoms using a three - step rating scale ( mild , moderate , severe ) . symptom severity was determined subjectively by the attending surgeon , who was asked not to select a similar patient solely on the basis of severity . patients who had the same level of severity as judged by all surgeons were then selected and analyzed to verify the reliability of the questionnaire . this study was approved by the ethics committee of the japanese society for spine surgery and related research . the reliability of the questionnaire was evaluated by determining the extension of the kappa coefficients . the kappa and weighted kappa coefficients were calculated based on a formula using microsoft office excel 2003 . kappa and weighted kappa coefficients of 0.4 or above were judged to be reliable.9 the 95% confidence intervals ( 95% ci ) were calculated for all reliability coefficients using the bootstrap method . a total of 350 patients participated in this study and completed the questionnaire twice following the project s plan . however , 135 patients were excluded because the severity of their symptoms had changed between the two interviews or they violated the interval period . of the remaining 215 patients , 54 were ineligible because of other musculoskeletal diseases , such as knee and hip osteoarthrosis . as a result , a total of 161 patients were available for the analysis in this study : 86 men and 75 women with a mean age of 57.7 years ( sd 16.3 years ) . the clinical diagnosis included degenerative lumbar canal stenosis in 49 patients , lumbar disc herniation in 44 , spondylolisthesis in 20 , spondylosis in 16 , degenerative disc disease in 13 , mechanical low back pain in 11 , and miscellaneous in 8 . the patients age varied from their twenties to their eighties , and symptom severity varied from mild to severe ( table 2 ) . neurological and physical status was evaluated for each patient using the current joa score rating system and finger - floor distance ( table 3 ) . neurological deficits varied from mild to severe , and trunk flexibility varied among the subjects as well . table 2distribution of age and severity of symptoms in the patient analyzed ( n = 161)no . of patients , by severity of symptomsage ( years)mildmoderateseveretotalmen20223730441940220450791176013832470618024800011total3443986women2023053045094061185094114607111197089118801102total3734475total no.717713161table 3current japanese orthopaedic association score rating system and fi nger to fl oor distance for the patients analyzed ( n = 161)parameterno.slr testnormal124307035<302motor functionnormal113slight weakness ( mmt : good)38severe weakness ( mmt : less than good)10sensory functionnormal80slight disturbance59severe disturbance22bladder functionnormal147mild dysuria12severe dysuria2finger to floor distance ( cm)-151 - 14-517 - 4-441514401524322534935447455475564465741immeasurable2total no.161slr , straight leg raising ; mmt , manual muscle testing distribution of age and severity of symptoms in the patient analyzed ( n = 161 ) current japanese orthopaedic association score rating system and fi nger to fl oor distance for the patients analyzed ( n = 161 ) slr , straight leg raising ; mmt , manual muscle testing face validity was checked in terms of the completion rate for filling out the questionnaire . the distribution of the answers for all question items was then checked to ensure that there were no biased answers . items remaining unanswered accounted for less than 5% in the first test , and there was no skewed distribution , such as  floor and ceiling  effects ( table 4 ) . table 4reproducibility of each item ( n = 161)choices for answeritem12345no answerq1 - 111743172.7%26.7%0.6%q1 - 232127219.9%78.9%1.2%q1 - 37683247.2%51.6%1.2%q1 - 44211926.1%73.9%q1 - 5778447.8%52.2%q1 - 63113019.3%80.7%q1 - 7689342.2%57.8%q1 - 86595140.4%59.0%0.6%q1 - 9728944.7%55.3%q1 - 10877454.0%46.0%q1 - 1135122421.7%75.8%2.5%q1 - 1241119125.5%73.9%0.6%q1 - 133612522.4%77.6%q1 - 1411545171.4%28.0%0.6%q2 - 118596616211.2%36.6%41.0%9.9%1.2%q2 - 215925229.3%57.1%32.3%1.2%q2 - 3259338515.5%57.8%23.6%3.1%q2 - 4357055121.7%43.5%34.2%0.6%q2 - 5151285351319.3%7.5%52.8%21.7%8.1%0.6%q2 - 6133666321138.1%22.4%41.0%19.9%6.8%1.9%q2 - 712879392217.5%5.0%49.1%24.2%13.7%0.6%q2 - 882788241225.0%16.8%54.7%14.9%7.5%1.2%q2 - 98427431515.0%26.1%46.0%19.3%3.1%0.6%q2 - 10135942341218.1%36.6%26.1%21.1%7.5%0.6%q2 - 111748562811110.6%29.8%34.8%17.4%6.8%0.6% reproducibility of each item ( n = 161 ) the test - retest reliability was confirmed by calculating the kappa and weighted kappa coefficients for each item ( tables 5a , 5b ) . both kappa and weighted kappa were more than 0.50 in all items , except in one item with 0.48 . the lower 95% ci exceeded 0.4 in all items , except in two items with 0.39 . this implied that the test - retest reliability of joabpeq was acceptable as a measurement of outcome . table 5akappa coefficient with 95% ci for items q1 - 1 to q1 - 14item95% ciq1 - 10.690.600.77q1 - 20.620.510.73q1 - 30.670.600.75q1 - 40.650.560.75q1 - 50.480.390.57q1 - 60.550.430.66q1 - 70.650.570.73q1 - 80.550.470.64q1 - 90.710.640.78q1 - 100.630.550.72q1 - 110.500.390.61q1 - 120.560.460.65q1 - 130.650.550.74q1 - 140.720.640.80ci , confidence intervaltable 5bweighted kappa coefficient with 95% ci for items q2 - 1 to q2 - 11itemweighted 95% ciq2 - 10.510.430.57q2 - 20.610.520.68q2 - 30.570.490.64q2 - 40.730.680.78q2 - 50.540.470.60q2 - 60.610.550.67q2 - 70.530.460.59q2 - 80.550.480.61q2 - 90.540.460.60q2 - 100.540.470.61q2 - 110.530.460.60 kappa coefficient with 95% ci for items q1 - 1 to q1 - 14 ci , confidence interval weighted kappa coefficient with 95% ci for items q2 - 1 to q2 - 11 a total of 350 patients participated in this study and completed the questionnaire twice following the project s plan . however , 135 patients were excluded because the severity of their symptoms had changed between the two interviews or they violated the interval period . of the remaining 215 patients , 54 were ineligible because of other musculoskeletal diseases , such as knee and hip osteoarthrosis . as a result , a total of 161 patients were available for the analysis in this study : 86 men and 75 women with a mean age of 57.7 years ( sd 16.3 years ) . the clinical diagnosis included degenerative lumbar canal stenosis in 49 patients , lumbar disc herniation in 44 , spondylolisthesis in 20 , spondylosis in 16 , degenerative disc disease in 13 , mechanical low back pain in 11 , and miscellaneous in 8 . the patients age varied from their twenties to their eighties , and symptom severity varied from mild to severe ( table 2 ) . neurological and physical status was evaluated for each patient using the current joa score rating system and finger - floor distance ( table 3 ) . neurological deficits varied from mild to severe , and trunk flexibility varied among the subjects as well . table 2distribution of age and severity of symptoms in the patient analyzed ( n = 161)no . of patients , by severity of symptomsage ( years)mildmoderateseveretotalmen20223730441940220450791176013832470618024800011total3443986women2023053045094061185094114607111197089118801102total3734475total no.717713161table 3current japanese orthopaedic association score rating system and fi nger to fl oor distance for the patients analyzed ( n = 161)parameterno.slr testnormal124307035<302motor functionnormal113slight weakness ( mmt : good)38severe weakness ( mmt : less than good)10sensory functionnormal80slight disturbance59severe disturbance22bladder functionnormal147mild dysuria12severe dysuria2finger to floor distance ( cm)-151 - 14-517 - 4-441514401524322534935447455475564465741immeasurable2total no.161slr , straight leg raising ; mmt , manual muscle testing distribution of age and severity of symptoms in the patient analyzed ( n = 161 ) current japanese orthopaedic association score rating system and fi nger to fl oor distance for the patients analyzed ( n = 161 ) slr , straight leg raising ; mmt , manual muscle testing face validity was checked in terms of the completion rate for filling out the questionnaire . the distribution of the answers for all question items was then checked to ensure that there were no biased answers . items remaining unanswered accounted for less than 5% in the first test , and there was no skewed distribution , such as  floor and ceiling  effects ( table 4 ) . table 4reproducibility of each item ( n = 161)choices for answeritem12345no answerq1 - 111743172.7%26.7%0.6%q1 - 232127219.9%78.9%1.2%q1 - 37683247.2%51.6%1.2%q1 - 44211926.1%73.9%q1 - 5778447.8%52.2%q1 - 63113019.3%80.7%q1 - 7689342.2%57.8%q1 - 86595140.4%59.0%0.6%q1 - 9728944.7%55.3%q1 - 10877454.0%46.0%q1 - 1135122421.7%75.8%2.5%q1 - 1241119125.5%73.9%0.6%q1 - 133612522.4%77.6%q1 - 1411545171.4%28.0%0.6%q2 - 118596616211.2%36.6%41.0%9.9%1.2%q2 - 215925229.3%57.1%32.3%1.2%q2 - 3259338515.5%57.8%23.6%3.1%q2 - 4357055121.7%43.5%34.2%0.6%q2 - 5151285351319.3%7.5%52.8%21.7%8.1%0.6%q2 - 6133666321138.1%22.4%41.0%19.9%6.8%1.9%q2 - 712879392217.5%5.0%49.1%24.2%13.7%0.6%q2 - 882788241225.0%16.8%54.7%14.9%7.5%1.2%q2 - 98427431515.0%26.1%46.0%19.3%3.1%0.6%q2 - 10135942341218.1%36.6%26.1%21.1%7.5%0.6%q2 - 111748562811110.6%29.8%34.8%17.4%6.8%0.6% reproducibility of each item ( n = 161 ) the test - retest reliability was confirmed by calculating the kappa and weighted kappa coefficients for each item ( tables 5a , 5b ) . both kappa and weighted kappa were more than 0.50 in all items , except in one item with 0.48 . the lower 95% ci exceeded 0.4 in all items , except in two items with 0.39 . this implied that the test - retest reliability of joabpeq was acceptable as a measurement of outcome . table 5akappa coefficient with 95% ci for items q1 - 1 to q1 - 14item95% ciq1 - 10.690.600.77q1 - 20.620.510.73q1 - 30.670.600.75q1 - 40.650.560.75q1 - 50.480.390.57q1 - 60.550.430.66q1 - 70.650.570.73q1 - 80.550.470.64q1 - 90.710.640.78q1 - 100.630.550.72q1 - 110.500.390.61q1 - 120.560.460.65q1 - 130.650.550.74q1 - 140.720.640.80ci , confidence intervaltable 5bweighted kappa coefficient with 95% ci for items q2 - 1 to q2 - 11itemweighted 95% ciq2 - 10.510.430.57q2 - 20.610.520.68q2 - 30.570.490.64q2 - 40.730.680.78q2 - 50.540.470.60q2 - 60.610.550.67q2 - 70.530.460.59q2 - 80.550.480.61q2 - 90.540.460.60q2 - 100.540.470.61q2 - 110.530.460.60 kappa coefficient with 95% ci for items q1 - 1 to q1 - 14 ci , confidence interval weighted kappa coefficient with 95% ci for items q2 - 1 to q2 - 11 measurement of the outcome is generally divided into two categories : generic and disease - specific measures.5,10 sf-36 has been commonly used as representative of a measurement of generic health status.5,7,10 the rdq and the oswestry disability index are widely used as disease - specific measurements for back pain.8,11 the joa score rating system for low back pain , developed in 1986 , was also a disease - specific measuring instrument for back disorders and injuries and has been widely utilized in clinical research and the decision - making process in japan . however , this is not a patient - based outcome measure reliable enough to describe the objective status of the function and quality of life ( qol ) of patients with low - back disorders . there has , to date , been insufficient psychometric analysis to confirm the validity and reliability of this joa score rating system . the project for developing the new questionnaire , joabpeq , was initiated to create a self - administered , disease - specific method for measuring low back pain . this instrument should include functions of the lumbar spine as well as health - related qol . the reliability of the questionnaire that includes the 25 suggested items was evaluated using psychometric analysis as part 2 of this project . kappa and weighted kappa coefficient were utilized to verify the test - retest reliability.12,13 in terms of external validity , biased data were inevitable because one criterion that was included was that the severity of the symptoms was expected to be at the same level between the two interviews . however , there was no bias on the choices of answer to each question . this implies that test - retest reliability was acceptable even if the subjects had symptoms of different severity . the older the patients were , the worse was the interpretation of each question . there were small numbers of patients of younger generations , such as those in their thirties and forties , in this study . thus , the reliability would not deteriorate even if the number of young people were to increase . in terms of english expression , there is a possibility of ambiguity in questions 12 and 111 , where double negatives ( two  no s  in the answer ) may be confusing . it is necessary to reconsider and revise the english expression so it is more easily understood by native english - language users . the number of choices for the answer in all questions varied from two to five , which is also a point to be reconsidered in the future . the current study demonstrated that the 25 items had enough reliability to describe the qol in patients suffering low back disorders . however , further studies are needed to complete the project , including a factor analysis to determine the underlying cluster of the questionnaire items , a formula for calculating the severity score , and confirmation of the responsiveness to the questionnaire . the tentative joabpeq with 25 items was confirmed to be reliable enough to describe the qol of patients suffering low back disorders .