lifestyle issues including physical activity [ 1 , 2 ] , diet [ 35 ] , smoking , alcohol consumption , and self - reported stress   have all been shown to predispose people to higher risk of cardiovascular disease . the simple lifestyle indicator questionnaire ( sliq ) remains the only short , easy - to - use instrument available for measuring cardiovascular lifestyle as a single construct . it measures five lifestyle risk factors and provides a score for each component , as well as an overall lifestyle score . initial psychometric testing of its reliability , internal validity , and basic external validity testing was published in 2008 . there was still a need to further assess the validity of the individual components . in 2010 , with funding through the healthy aging research program of the newfoundland and labrador centre for applied health research , we conducted further validity testing . this paper reports on the concurrent validity of the physical activity , diet , alcohol , and stress components of the sliq . we also report on convergent validity of the whole instrument and compare the overall sliq scores to scores on a similar series of questions that have been correlated with cardiovascular morbidity and morbidity . we recruited patients aged 40 and above from three different family physician clinics that are part of a practice - based research network and have participated in research studies previously . the practices have electronic medical records ( emrs ) . randomly generated lists of patients in three age groups , 4059 years , 6079 years , and 80 + years , were compiled by the clinic staff . the letters briefly explained the study and provided the phone number of the research assistant to be contacted if they were interested in taking part . subsequently two further blocks of 100 people per age group were contacted until we had sufficient sample size . we sent letters to 900 people in order to recruit 193 consenting patients who completed all the questionnaires . using an alpha of 0.05 and a beta of 0.2 , we calculated that 153 participants would be needed to make sure that a correlation of 0.2 or more was statistically different from a correlation of zero . therefore , our sample size of 193 provided sufficient power since all our correlations turned out to be greater than 0.2 . each participant provided basic demographic data and completed the sliq instrument , a detailed diet history questionnaire ( dhq ) [ 11 , 12 ] , the social readjustment rating scale ( srrs ) [ 13 , 14 ] , question 1 on the sf36 health status questionnaire [ 1518 ] , and a survey of eight questions on cardiovascular risk proposed by spencer et al . . moreover , each participant wore a pedometer for three days and returned the pedometer to the research assistant . using a pedometer for three days has been shown to be highly correlated with the level of physical activity [ 20 , 21 ] . the pedometer used , the sportline sl330 , has been shown to be equivalent to a reference pedometer which measures within 3% of the actual number of steps . the dhq collects detailed information on type and quantity of different foods ( vegetables , fruit , grains , meat , fish , dairy products , etc . ) the higher the score the higher the likelihood of experiencing stress [ 13 , 14 ] . the sf36 is a health status measurement tool used in over 4000 published studies worldwide . its psychometrics has been assessed in all age groups , genders , and many races and countries . question 1 on the sf36 is used as a measure of self - assessed health status [ 1518 ] . question 1 asks  in general , would you say your health is  excellent  very good  good  fair  poor .  in 2005 , spencer et al they compared the response to eight questions on diet , activity , smoking , alcohol , and bmi to a person 's likelihood of dying . people with a score of 5 out of 8 or higher had a 5 times higher likelihood of dying within 5 years . we will compare the sliq lifestyle score to the score on this eight - question scale . concurrent validity is determined by comparing the score on the instrument of interest ; in this case the sliq , with the score on a reference standard  a measurement tool that is known to accurately measure that same construct . concurrent validity in this study is determined for physical activity by comparing the physical activity score on the sliq with the steps on a pedometer ; it is determined for diet by comparing the raw diet score on the sliq with the diet score on the dhq ; it is determined for alcohol by comparing the raw alcohol component on the sliq with the alcohol score on the dhq ; and it is determined for stress by comparing the raw stress score on the sliq with the stress score on the srrs . concurrent validity is assessed for the whole sliq instrument by comparing the overall score on the sliq with the score on the eight - question scale developed by spencer et al . for concurrent validity , we hoped to achieve correlation coefficients of 0.4 or higher and ideally larger than 0.6 . convergent validity is measured by comparing the instrument in question with another instrument that measures a related , but different , construct . in this case , we used the responses to the first question on the sf36 which is a self - assessment of one 's health status . while lifestyle and health status are related , they would not be expected to have high correlation since a change in one may precede or follow the other rather than necessarily exist concurrently . measuring human behaviour is not an exact science and rarely can it be done with the precision found in fields such as engineering . to increase the accuracy of measurement , we often have to use long and detailed questionnaires or similar meticulous processes . however , what is preferred is a measure that is short and easy , especially in a clinical setting where providers are busy and patients may be ill . similarly , in a health research setting the issue of participant burden has to be considered and long detailed questionnaires should be avoided . in order to efficiently measure some behaviours in clinical and research settings , shorter health measurement scales are developed and compared to the longer detailed assessments to determine if they can be used to realistically assess the particular behaviour or health issue . the original development process started eight years ago with over 30 questions , and , using factor analysis , the number of questions was decreased to twelve . it is this 12-question sliq that was tested in the initial psychometrics study published in 2008   and which was used in this current study . the sliq has 12 questions ; three on diet , three on physical activity , three on alcohol consumption , two on smoking , and one on stress a french version is also available , but none of the psychometric testing has been carried out in french . each component is assigned a category score of 0 , 1 , or 2 , based on raw scoring of questions related to each component . component scores are summed to give a sliq score from 0 to 10 ( 0 = very unhealthy , 10 = very healthy ) . categorically , a person is considered  unhealthy  if they have a sliq score of between 0 and 4 ,  intermediate  if the sliq score is between 5 and 7 , and initial psychometric testing of the sliq   resulted in a test - retest reliability between 0.63 and 0.97 ; a cronbach  of 0.58 for diet and 0.6 for physical activity , and blinded external validity of 0.77 . validity was assessed by determining the correlation coefficients between the component raw scores on the sliq and the appropriate reference standards ( dhq , srrs , question 1 on the sf36 , and step per day on the pedometer ) . anova was conducted to determine if the three categories , unhealthy , intermediate , and healthy , were separately distinguishable populations for each component and for the overall sliq score . finally , we compare the overall sliq score with the score on the eight - question risk assessment developed by spencer et al . . this research was reviewed and approved by the human investigation committee of memorial university of newfoundland , canada . one hundred and ninety - three adults completed all the questionnaires allowing correlational statistics to be completed . the mean age was 65 years ( sd = 14.5 years ) with a range 4095 years ; nearly sixty - six percent were females . details of education , marital status , income , and bmi are shown in table 1 . the population was distributed through the socioeconomic spectrum but was financially better and more educated than the general population . the majority ( 75% ) the details of the correlations are presented in table 2 and figures 1 , 2 , 3 , 4 , 5 , and 6 . the sliq diet and alcohol components correlate well with diet and alcohol as assessed by dhq ( r = 0.679 and 0.665 , resp . ) ; there is also good correlation between the sliq physical activity component and the number of steps over three days as measured by a pedometer ( r = 0.455 ) . the sliq stress component did not correlate as well as we had hoped with stress as measured by the stressful life events count on the srrs ( r = 0.264 ) . the correlation with stressful life events is negative because on the sliq a higher score for stress means less stress whereas on the srss a higher count indicates more stress . the overall sliq lifestyle score correlated reasonable well with the eight - question risk scale ( r = 0.475 ) , and people who score 5 or higher on the eight - question scale had a mean sliq score of 7.2 ( sd 1.4 ) while those who scored less than 5 on the eight questions scale had a mean sliq score of 5.8 ( sd 1.8 ) ; these two means were from statistically different populations , p = 0.001 . the final comparison , between the sliq lifestyle score and self - assessed health on the sf36 ( question 1 ) , is considered an assessment of convergent validity rather than concurrent validity in that the expectation is not that the correlations would be high but rather in the fair or moderate range . this is because lifestyle and health status are not measurements of the same construct but rather related constructs . hence , a correlation of r = 0.303 is in the range we were expecting . the categorization of individuals as unhealthy / intermediate / healthy was assessed to determine if these three groups were from separate populations ; that is , whether the mean and standard deviations of the sliq scores in these three groups were separated such that there was very little overlap . we used anova to determine the mean and standard deviations and 95%  ci for these groups . the data in table 3 shows that the three categories are clearly separated with almost no overlap . the correlation coefficient , usually designated as  r  , quantifies the strength of the linear relationship between two variables . an r of zero indicates no correlation and an r of 1 means a perfect linear relationship . opinion on how a given level of correlation between 0 and 1 should be interpreted varies in the literature . some investigators believe a correlation between 0.0 and 0.25 represents a weak relationship , 0.260.50 a moderate relationship , 0.510.75 a strong relationship , and greater than 0.75 a very strong correlation . others divide the correlation coefficient into three categories where an r between 0.0 and 0.3 indicates a weak relationship , 0.3 to 0.7 indicates a moderate relationship , and > 7 indicates a strong relationship . in 2003 , hemphill   reviewed the literature that reported correlation coefficients and divided them into tertiles : one - third reported coefficients < 0.2 , the middle third reported coefficients between 0.2 and 0.3 , and the upper third reported coefficients > 0.3 . and finally cohen   uses a benchmark of r = 0.50 as a level of strong correlation . the interpretation systems described above would place most of these r values in the moderate - to - strong categories . as mentioned in the results , the correlation for sliq stress score versus this is expected  all sliq components are scored such that a higher number means a better lifestyle ( in this case lower stress ) . the absolute value of the correlation for the stress component is the lowest of all the components , and we considered dropping it from the scale . however , the sliq measures the person 's assessment of their current stress level while the srrs simply scores stress events in a person 's life over the previous year . people deal with stress differently , and the person 's assessment of their own feelings of stress may be more important . validity correlation coefficients for diet , physical activity , and alcohol consumption are sufficiently strong to make the sliq useful in research and clinical settings . similarly , its correlation with the eight - question scale , which themselves have been shown to predict mortality , increases the sliq validity . assessments of the sliq sensitivity to change and its predictive validity are both underway . 
 limitations . the chosen reference standard , and the dhq is a long and detailed questionnaire and is probably as good as any we could have chosen . the srrs takes an interesting approach to assessing stress in a person 's life but one could argue there are more modern approaches , and perhaps we should have chosen one of those . it has been suggested that we should have used an accelerometer to measure actual physical activity rather than a pedometer . it has also been suggested that since the eight questions used by spencer et al . have been shown to predict mortality , why not we use them rather than the sliq for assessing lifestyle . one reason is that spencer included bmi which is not a lifestyle but rather a consequence of lifestyle ; moreover , there have been no psychometrics conducted on the eight questions unlike the sliq which has a developing literature . finally , the study population was somewhat skewed towards women ( 65% ) and older age group ( mean age 65 years ) . we believe the sliq is sufficiently valid when compared to reference standards to be useful as a brief assessment of an individual 's cardiovascular lifestyle in research and clinical settings .
lifestyle issues including physical activity , diet , smoking , alcohol consumption , and self - reported stress have all been shown to predispose people to higher risk of cardiovascular disease . 
 this study provides further psychometrics on the simple lifestyle indicator questionnaire ( sliq ) , a short , easy - to - use instrument which measures all these lifestyle characteristics as a single construct . 
 one hundred and ninety - three individuals from st . 
 john 's , newfoundland , and labrador , canada completed the sliq and reference standards for diet , exercise , stress , and alcohol consumption . 
 the reference standards were a detailed diet history questionnaire ( dhq ) , the social readjustment rating scale ( srrs ) , the sf36 health status questionnaire , and a survey of eight questions from a cardiovascular risk questionnaire . 
 physical activity score was compared with number of steps on a pedometer . 
 correlations between scores on the sliq and the reference standards were the sliq versus dhq ( r = 0.679 , p = 0.001 ) , sliq versus pedometer ( r = 0.455 , p = 0.002 ) , sliq versus alcohol consumption ( r = 0.665 , p = 0.001 ) , sliq versus srrs ( r = 0.264 , p = 0.001 ) , sliq versus eight - question risk score ( r = 0.475 , p = 0.001 ) , and sliq versus question 1 on sf36 ( r = 0.303 , p = 0.001 ) . 
 the sliq is sufficiently valid when compared to reference standards to be useful as a brief assessment of an individual 's cardiovascular lifestyle in research and clinical settings .