the concept of quality of life [ quality of life ( qol ) ] was established in the field of medicine in the 80 s . until today however , a universally approved definition of qol is lacking . an established approach to qol was formulated by bernheim , who defined qol as an individual and emergent construct , the resultant of a great many interactions , and of a different order than its contributing components . therefore , the assessment of overall qol has to allow individuals to use their own internal standards and priorities as references . according to this definition , the amnestic comparative self - assessment [ amnestic comparative self - assessment ( acsa ) ] uses a one - dimensional , self - anchoring scale . its endpoints refer to the subject s best and worst times in life and his / her actual overall well - being is rated between these internal anchors . the acsa has been employed in various adult samples , for example cancer patients , locked - in - syndrome patients , or organ donors . it has proven to be a sensitive measure , possessing greater sensitivity than conventional single - item measures of life satisfaction and happiness . however , in children and adolescents , the acsa has to our knowledge not yet been adopted . this may be because self - anchoring scales , like the acsa , increase processing time and cause more drop - outs as compared to fixed - anchoring scales , or because completing the acsa requires that a person has life experience , which sets the standard of comparison . on the other hand , its use would enrich future epidemiological or clinical investigations , because it is a sensitive , efficient and economic instrument . developmental processes in the course of adolescence strengthen the ability for abstract thinking and metacognitions . with increasing age , thus , adolescents may well be able to specify their overall qol and complete the acsa . in future research , the acsa could be used as an alternative or in addition to the health - related approach to qol , which is at present predominant in children and adolescents . health - related quality of life [ health - related quality of life ( hrqol ) ] is defined as a multidimensional construct pertaining to the physical , emotional , mental , social and behavioral components of wellbeing and function as perceived by the patients and/or observers . thus , the assessment of hrqol includes ratings on distinct subscales , which are considered relevant to qol for the majority of a cultural group . however , we can not know to what extent the hrqol dimensions and their interactions contribute to an individual s overall qol , because the weights of the distinct dimensions remain unknown and , therefore , immeasurable . by contrast , the acsa bypasses biases due to cultural differences , peer - relativity , and social desirability , because individuals are required to integrate the multiple facets of qol based on their personal life - experience . peer - relativity and social desirability might affect qol - measures that do not use internal standards as references especially in adolescents because , in this age - group , relations to others are of major importance . therefore , an instrument like the acsa , which is not susceptible to external influences , would be of special value in adolescent samples . due to its independence of cultural and social influences , the acsa could be adopted in cross - cultural studies or for comparisons between adolescent populations who might differ in their external standards . we therefore consider the acsa a convenient instrument , whose implementation could make a valuable contribution to qol research in adolescents . the aim of the present study was to investigate the usability of the acsa in adolescents and compare results to that of the kiddo - kindl , a validated and widely - used instrument specifically developed for 12- to 16-year - olds . this correlation should be consistently high in all age groups of the adolescent sample . according to the findings of van acker and theuns , who reported more drop - outs in self- as compared to fixed - anchoring scales , we expected responds rates to the acsa to be lower than those to the hrqol - measure . acsa - respondents and non - respondents were analyzed for systematic differences between each other in sex , age , educational level , and hrqol . the here presented data were collected in the context of a study about the association of sleep problems and hrqol in german adolescents . study materials consisted of a covering letter , a letter of agreement , questionnaires ( see below ) , and the assessment of demographic variables ( including age , sex , and type of school ) . documents were distributed in schools , youth centers , and sports clubs by the experimenters . the parents of all participants gave written informed consent prior to taking part in the study . the study was conducted in accordance with our institution s ethical review committee and the standard ethical guidelines as defined by the declaration of helsinki ( world medical association ) . subjects are instructed to memorize the best and worst times in their lives and rate their actual overall well - being on an ordinal visual analog scale ranging from -5 to + 5 in relation to their individual anchors . kiddo - kindl : the kiddo - kindl questionnaire was constructed for children aged 12 - 16 years . it consists of 30 items assessing hrqol on six subscales ( physical well - being , emotional well - being , self - esteem , family , friends , and everyday functioning / school ) . transfor med scores for the total score and each subscale can be derived ranging from 0 to 100 on an interval scale . the empirical evaluation of the kiddo - kindl has shown good reliability , validity , and acceptance in adolescents . all analyses were conducted with spss statistics 18 ( ibm deutschland gmbh , ehningen ) . independent samples t - tests and chi - square tests were conducted to compare acsa - respondents and non - respondents . since the asca is answered on an ordinal scale , reported correlations are spearman - rho coefficients or spearman partial correlation , indicating convergent validity . analyzing divergent validity , group differences between boys and girls were tested using independent samples t - test for the kiddo - kindl , and the non - parametric mann - whitney - u - test for differences in acsa ratings . the sample comprised 92 adolescents ( 50 girls , 42 boys ) aged 11 - 17 years ( m=13.67 , sd=1.34 ) . acsa - respondents and non - respondents did not differ significantly in age , sex , type of school or kiddo - kindl total score ( table 1 ) . frequencies of acsa score ( figure 1 ) show a left skewed , platykurtic distribution ( skewness : -0.76 , excess kurtosis : -2.68 ) . the correlation of the kiddo - kindl total score ( m=70.78 , sd=11.07 ) and the acsa rating ( md=2.00 , range=10 ) was medium ( r=0.50 ) . the correlation of the kiddo - kindl total score and the acsa was still medium when controlled for age ( partial r=0.53 ) . as depicted in table 2 , correlations of kindl subscales and the acsa varied between r=0.07 , ns ( everyday functioning / school ) and r=0.41 , p<0.01 ( emotional well - being ) . again , controlling for age did not significantly affect the correlation coefficients . in acsa - respondents , kiddo - kindl total score differed significantly between boys ( m=74.02 , sd=9.19 ) and girls ( m=68.99 , sd=11.78 , t(67)=-1.97 , p=0.05 ) . correspon dingly , boys ( mean rank : 39.51 ) also reported higher acsa scores as compared to girls ( mean rank : 30.61 , mann - whitney - u=441.50 , p=0.06 ) . the aim of the present study was to investigate the applicability of the acsa in adolescents and to compare it to the kiddo - kindl , an established and well - evaluated measure of hrqol . we could confirm our first hypothesis of a positive relationship between overall and health - related qol : the correlation between the acsa and the kiddo - kindl score was moderate and positive . this moderate correlation indicates common aspects captured by both measures , such as emotional and physical well - being , but also indicates differences , which are specifically obvious for the kiddo - kindl subscale everyday functioning . given the holistic definition of overall qol , the acsa score correlated most highly with the total kiddo - kindl score . all separate subscales correlated similarly with the acsa , suggesting that these domains contribute equally to the overall construct . the subscale everyday functioning is an exception as it does not correlate with the acsa . this scale mainly assesses school - related aspects , like interest in lessons or fear of bad marks . apparently , these aspects were not associated with the overall qol of adolescents in our sample . furthermore , we confirmed our second hypothesis and found that the majority of adolescents are able to complete the acsa . however , 25% of our sample refused to answer the acsa . five participants stated stupid question , i do nt think and feel in those categories or ? . but the reduced response rate can not be considered a problem exclusively occurring in adolescents . self - anchoring scales , like the acsa , cause comparably elevated drop - out rates in adults ( 26.98% ) . thus , not only adolescents , but also adults have reduced response rates as compared to fixed - anchoring scales . acsa - respondents and non - respondents did not differ in demographic variables or hrqol . therefore , acceptance of the acsa did not depend on individual characteristics ; not even on the participants age . this is remarkable , because the study included adolescents from a broad age range ( 11 - 17 years ) , who were equally able to complete the acsa . biases due to distractors or parental influence on adolescents answers can not be ruled out . secondly , our sample was recruited in a large city and might not be representative for adolescents from less urbanized regions . future investigations in larger representative samples would be desirable to further explore convergent and divergent validity of the acsa in adolescents . future research might also address the question of how completion rates could be increased . in this regard , the immediate presence of an experimenter or a modified , age - specific instruction may prove helpful . to conclude , the acsa is applicable in the majority of adolescents and can be used in future investigations to assess overall qol , for example in epidemiological and cross - cultural surveys , clinical populations or as an outcome measure in intervention studies . the acsa is as well accepted in adolescents as other self - anchoring scales in adults , and acceptance and validity do not depend on age or other individual characteristics .
the amnestic comparative self - assessment ( acsa ) is a sensitive , efficient , and economic instrument to assess overall quality of life in adult populations . 
 the present study investigates the applicability of the acsa in an adolescent sample and compares it to a measure of health - related quality of life , the kiddo - kindl . 
 the sample comprised 92 adolescents ( 50 girls , 42 boys ) aged 11 - 17 years ( mean age : 13.67 , standard deviation : 1.34 ) . 
 of the investigated sample , n=69 ( 75% ) completed the acsa . 
 no significant demographic differences were found between acsa - respondents and non - respondents . 
 the correlation of the kiddo - kindl and the acsa was moderate ( r=0.50 ) . 
 the kiddo - kindl subscales and the acsa correlated between r=0.07 and 0.41 . 
 the majority of adolescents are able to complete the asca , and its acceptance and validity are independent of age . 
 thus , future investigations could adopt the acsa in adolescents to assess overall quality of life .