Design Psychometric study

Of content validity through expert judgment. The information collection process was carried out in the period from October to December 2021.

Population and sample

The population was made up of five medical professionals with a specialty in internal medicine and nutrition. For the selection of expert judges, aspects of academic training, research, and previous experience as^10,11judges in validation studies , as detailed inTable 1.

Instrument

The CAP-salt questionnaire was developed by Grimes Instrument et al.¹². This questionnaire was originally developed in Australia, in the English language. It has three blocks: 1) knowledge of salt made up of seven questions, 2) attitudes towards salt consumption made up of four questions; and 3) practices on salt with five questions. The instrument has dichotomous, polytomous, and selection response options. multiple with a single answer¹³.

The questionnaire was submitted to the translation process by a translator from the team of the Institute of Biomedical Sciences of the Ricardo Palma University (INICIB-URP), into Spanish and subsequently retranslated to analyze whether the items maintained the purpose for which they were elaborated¹².Figure 1

Figure 1: Questionnaire translation process 

One of the most applied strategies to calculate evidence of content validity of an instrument is to submit it to expert judgment^15-18. The task of the judges is to evaluate the content of the items; for the evaluation of the instrument, the evaluation of each item was carried out through the Expert through three indicators to be evaluated: clarity, coherence, and relevance, whose rating is given through six response options to eliminate the intermediate position and obtain more reliable responses^20-22. Clarity refers to the syntax and semantics of each item. Coherence evaluates if the item has a logical relationship with the indicator or dimension that it is measuring. Relevance estimates whether the item is essential to measure the indicator. Sufficiency assesses whether the set of defined items is sufficient to measure a dimension.

In addition, each expert judge completed the validation certificate. They fully evaluated the assessments related to the unity of the items, the breadth of the content, and the relevance of the original instrument.

Procedure

The data obtained was stored in Microsoft Excel. The content validity coefficient using Aiken's V was calculated through the application developed by Merino and Livia²³, the same one that provides confidence intervals using the scoring method. The calculation of the exact critical value of Aiken's V was obtained with the formula proposed by Aiken²⁴.

Statistical analysis

To calculate the degree of agreement among the expert judges, Aiken's V was used. This coefficient presents values ​​ranging from 0.00 to 1.00, where the value of 1.00 would indicate the maximum agreement among the judges in the contents. Evaluated. The calculation of the Aiken V coefficient takes into account the average of the grades, the minimum possible score, and the range of possible scores. For the purposes of controlling the sampling error, it is important to specify the range of possible values ​​that the coefficient would assume using the intervals of trust²⁵.

The analysis of the items was carried out based on the opinions of the expert judges and the results of Aiken's V according to the semantic adaptation guidelines found in the guidelines for the translation and adaptation of the tests¹⁴.

As a decision criterion to keep an item, a value of 0.7 was considered for the lower limit of the confidence interval and 1 for the upper limit²⁶, a coefficient of variation less than 25%, or that at least two judges request the exclusion of the question.

Ethical aspect

The participation of each expert was voluntary and was accepted with the signing of the informed consent. Likewise, it had the approval of the Research Ethics Committee of the Faculty of Human Medicine of the Ricardo Palma University, number PI-007-2021.

General quantitative analysis

The global evaluation of the questionnaire showed that Aiken's V coefficient in the aspects of clarity, relevance, and sufficiency reached values higher than 0.80.

Specific quantitative analysis

Table 2reports the results on the clarity of the items quantified using Aiken's V coefficient. As can be seen, the items obtained favorable evaluations on clarity, presenting V values greater than 0.80, a critical value less than 0.7, in addition to a coefficient of variation less than 25%; therefore, none of the items He was removed.

Considering the coherence parameter,Table 3, it should be noted that the items obtained Aiken's V coefficient values above the established lower critical value of 0.71, and also presented a coefficient of variation of above 20%, which would confirm the decision not to exclude any of them.

Table 4reports the results on the relevance of the items calculated using the Aiken V coefficient, the results shown show favorable indices in the calculation, which added to optimal values in the coefficient of variation support the decision to include them in the final instrument.

Main findings

In general, it has been suggested that the use of unreliable and unvalidated questionnaires to measure knowledge about nutrition is responsible for the inconsistencies observed in the relationships between knowledge and eating behaviors²⁷.

The findings demonstrated the validation process of the CAP-salt instrument presents evidence of content validity through expert judgment with positive Aiken V values ​​in the categories analyzed, these being clarity, coherence, and relevance^17,23,24.

Comparison with other studies

This questionnaire is the first to analyze consumer attitudes, knowledge, and behavior related to salt consumption in developing countries.

Similar studies have been carried out in developed countries such as Australia^12,28, Ethiopía²⁹, Canadá³⁰y Kazakhstan³¹. These political and interested parties responsible reinforce the importance of knowing the phenomenon to be ableto implement strategieson responsible consumption of it.

In the process of construction and/or adaptation of a measurement instrument, content validity represents the first level of evidence of validity on the content of a test and the construct that is intended to be measured. The content refers to the topic, writing, format, and presentation of the items or questions of the instrument^13,18.

This questionnaire is not measured in a sum of values ​​about whether the person has high or low knowledge, attitude or practice, so it does not work in a dichotomous or even polytomous manner (with three answers). In this way, the way in which it should be handled is through each question individually and to be able to make comparisons between other variables of interest, such as gender, and the presence of some comorbidity, among others.

Significance for public health

Excessive consumption of sodium in the diet is a major public health problem both nationally and internationally. Therefore, because for monitoring and providing reliable information toinvolved in the initiatives to reduce this, it is necessary to have a tool that allows me to measure the CAP-salt in the population.

Knowing the goals that experts set for salt intake can help consumers make better-informed decisions when buying processed foods and be more mindful and sensitive when cook ing or eating. A better understanding of the relationship between salt and sodium can also make understanding nutrition information on food labels easier. In itself, knowing the CAP-salt can help consumers make better-informed decisions when buying processed foods and be more aware and sensitive when cooking or eating.

Strength and limitations

The strengths of our study are the inclusion of experts from different specialties of human medicine, with the aim of obtaining different points of view. Second, this questionnaire has been validated so that Peruvians could take it from different parts of the country, which gives it heterogeneity for the use of this tool. Third, since the questionnaire includes only 16 questions, it requires little time and effort on the part of the people taking it.

Among the study's limitations were the choice and availability of the judges, specialists, and translators and the organization of the time allocated to the validation process. Second, since the study is only focused on the Peruvian population, the results may not be generalizable to other countries, particularly in countries with different behaviors and dietary patterns and, therefore, different sources of food consumption. sodium. The INICIB-URP work team has future work underway to explore the factorial validity of the questionnaire in various populations.