| Objective: Define the conception,connotation and extension of public health safety literacy(PHSL),establish a PHSL evaluation index system,develop the Chinese public health safety nutrition scale,and test the reliability,validity and feasibility of the scale.The purpose of this study is to provide tool support for measuring the level of public health safety literacy,exploring the influencing factors of public health safety literacy and formulating relevant intervention measures.To provide a scientific basis for China to effectively carry out the construction and practice of public health safety system.Methods: The scale development was conducted using techniques related to classical test theory(CTT)and item response theory(IRT).The main steps and methods are:(1)Conceptualization: Define the conception,connotation and extension of PHSL.Through literature search and expert consultation,the theoretical concept of "public health and safety literacy" was proposed,the conception,connotation and extension of PHSL were defined,and the dimensions and domains were established.(2)Forming the evaluation index system and the item pool of PHSL: Based on the theoretical conception,dimensions and domains,a system of primary,secondary and tertiary evaluation indicators is constructed.Preparation of a pool of PHSL items on the basis of tertiary indicators.the definition,dimensions and item pool of PHSL are further modified and improved through the expert in-depth interview method.(3)Screening items: Through the expert nominal group method,10 experts in relevant fields were invited to fully discuss and vote on the item pool,and the items with more than 8 experts supporting retention in the voting results were entered into the Delphi expert consultation alternative pool;Using the Delphi expert consultation method,30 experts with authority and representativeness in relevant fields were invited to conduct letter consultation,and the importance,necessity and feasibility of the entries were evaluated and scored by them.At the end of 2 rounds of Delphi expert consultation,the items were screened by statistically analyzing the degree of positivity of experts,the degree of coordination of expert opinions,and the scores of each item to form the initial questionnaire items on public health and safety literacy.Items were developed into the initial PHSL questionnaire(three parallel questionnaires of approximate validity,A,B,and C).(4)Field verification: according to the calculation of the required sample size,according to the principle of multistage stratified whole-group random sampling,residents aged15-69 in four provinces of Hubei,Guangdong,Beijing and Sichuan were selected for field verification to validate the initial questionnaire.(5)Item reduction: The initial questionnaire was firstly reduced by using CTT,and on the basis of CTT,the retained items were continued to be reduced by using IRT.Among them,CTT was used to reduce the items by correcting the Corrected item-total correlation(CITC)and the cronbach’s alpha coefficient(Cronbach’s α),the item-dimension correlation coefficient(IDCC),the discrimination,and the exploratory factor analysis(EFA)in five methods.Item response theory reduces the items by calculating the item differentiation parameters(a),difficulty parameters(b),and information content,and plotting the item characteristic curves(ICC)and item information curves(IIC)of the items.According to the item deletion criteria corresponding to each method,the items that do not meet the criteria were deleted and the items of good quality were retained to form the final scale.Among them,CITC and Cronbach’s α examine the internal consistency of the scale;if the CITC of a question item was <0.3 and the total Cronbach’s α of the questionnaire increases after deleting a question item,it was deleted;IDCC examines the correlation size of each question item and the dimension it belongs to,if the IDCC of a question item was <0.4,the item was deleted;the discrimination method examines whether the items can distinguish respondents with different levels of public health and safety literacy,including the difficulty index,the discrimination index,and the critical ratio.If the difficulty index of question items was <0.2 or >0.9,the discrimination index was<0.2,and the critical ratio t-test was t<3 or P>0.05,it was deleted;EFA explored the internal structure of the data to find the common factor for the purpose of dimensionality reduction and condensing the number of question items,and if the variance of the common factor was <0.2 or the factor loading of the question items was<0.5,and the factor loading was small in all common factors after rotation,it was deleted.The a-parameter reflects the ability of the item to discriminate between different subjects’ ability levels,and was deleted if the a-parameter of the item was<0.30;the b-parameter reflects the difficulty of the item,and was deleted if the b-parameter of the item was outside the range of [-3,3];the ICC curve reflects the extent to which the item can truly and effectively measure potential ability,and was deleted if the ICC monotonicity of the item was unsatisfactory;the IIC curve reflects the extent to which the item or scale can The IIC curve reflects the amount of information that the item or scale can provide in estimating the subject’s ability,and if the IIC curve of the question item had no peak or was flat,and the amount of information was too small,it was deleted.(6)Scale evaluation: The cronbach’s alpha coefficient and split-half reliability coefficient were used to evaluate the reliability of the scale;content validity index was used to evaluate the content validity of the scale,exploratory factor analysis and model fit index were used to evaluate the structural validity and model fit of the scale;differential item functioning test was used to evaluate the stability of the scale;collection rate and mean response time were used to evaluate the feasibility of the scale.(7)Determine the passing score: The ROC curve method was used to determine the passing scores.The curve was plotted with sensitivity as the vertical coordinate and1-specificity as the horizontal coordinate.The tangent point as close as possible to the upper left corner of the curve was selected as the best critical point,and the corresponding score was the passing score.Results:(1)PHSL conception,connotation and extension: This study defines PHSL as the ability of individuals to prevent,control the occurrence and development of public health safety and reduce or avoid its hazards by acquiring,understanding,and applying public health safety-related information and services to detect,manage,or eliminate risk factors that threaten health and life safety.It includes 3 dimensions of public health safety awareness,knowledge and skills,and covers 5 areas of major infectious disease outbreaks,group disease of unknown etiology,major food poisoning and occupational poisoning,and other public health emergencies that endanger public health and safety.(2)PHSL evaluation index system and item pool: This study constructed a three-level evaluation index system for PHSL,with the primary indicators being the 3 dimensions of PHSL awareness,knowledge and skills;the corresponding secondary indicators were12 in total;the tertiary indicators were constructed on the basis of the secondary indicators,and the item pool was formed on the basis of the tertiary indicators,containing a total of 172 items.(3)Screening items: 90 items were screened out from172 items after voting by the nominal group of experts.Based on the principle of approximation of validity,the 90 items were evenly distributed into three parallel questionnaires(30 items per volume),A,B and C,for Delphi expert consultation.The positive degree of expert consultation in the 2nd round was 90.0% and 81.5%,respectively.The importance,necessity,and feasibility coordination coefficients of the experts were higher in round 2 than in round 1.The mean importance,necessity,and feasibility scores of the 90 items were >3.5.Therefore,all 90 items met the requirements.(4)Field verification: The screened items were compiled into an initial PHSL questionnaire(three parallel questionnaires of approximate validity,A,B,and C.A total of 2809 questionnaires were returned from four provinces,with 2809 valid questionnaires and 100% questionnaire return efficiency.(5)Item reduction: In this study,the parallel questionnaire C(30 items in total)with the best internal consistency coefficient was selected for scale development and question reduction.Based on the five methods of CTT,a total of 13 items were retained after removing the items that did not meet the criteria from the 30 items.The 13 retained items were further analyzed by IRT,and the 2 items that did not meet the criteria were deleted to form the final PHSL scale containing 11 items.(6)Scale evaluation: The reliability of the scale was good,with Cronbach’s alpha coefficient of 0.936 and split-half reliability of 0.798;the structural validity was good,with content validity index of all items >0.8,factor loadings >0.7,cumulative variance contribution rate >63%,and model fit indicators RMSEA,TLI,CFI,etc.all meeting the fit criteria;the stability of the scale was good,with no functional differences in items by gender,income level,or household registration for all question items;the questionnaire was 100% effective.According to the time spent in the field survey,it took less than 2 min per person to complete a scale developed in this study,and the feasibility was good.(7)Scale passing score: the area under the ROC curve was 54.1%.The total score of the scale was 44,and the passing score was 32.5.The passing rate of public health and safety literacy in this survey was66.01%.Conclusions: This study developed the Chinese Public Health Safety Literacy Scale in six steps by defining the conception of PHSL,constructing the PHSL evaluation index system and item pool,screening items,preparing the initial questionnaire,field verification survey and item reduction,and the scale has good reliability,validity,stability and feasibility.It is scientifically reliable,simple and easy to use,and has good application prospects for the rapid assessment of PHSL for the public in China. |
PDF Full Text Request