Providing a psychological scale to measure COVID-19 phobia in the Indonesian version: a brief report on validation of C19P-S via Rasch Analysis

: Specific phobias such as COVID-19 are new and are believed to have developed rapidly since the beginning of the Pandemic established by the WHO in March 2020. Unfortunately, the development of psychological measurement tools related to COVID-19 Phobia is still inadequate in Indonesia. This study aims to validate the Indonesian version of the Phobia scale against COVID-19 (C19P-S). It was recorded that 220 respondents from various groups were involved in this study. The data collected were analyzed by means of the Rasch Model to determine the accuracy of the validated psychometric properties of the scale. The study findings show that the Indonesian version of C19P-S has sufficient psychometric properties and can measure phobia against COVID-19 in the sample group tested. Of the 20 items of the C19P-S, we recommend 18 items that are suitable for use by users of this scale.


Introductions
In 2020 is a very painful year for countries in the world due to the spread of Corona Virus Disease 2019 .Various policies have been taken by countries affected by COVID-19 as a response measure and to reduce the rate of spread of COVID-19 including shutting down and limiting human activities (physical distancing, self-isolation and social distancing) and following the health protocol campaign issued by the World Health Organization (WHO).From various points of view, COVID-19 has drained a lot of energy, focus and resources from each country to reduce the impact felt by its people in different sectors of life since it was first discovered in December 2019 in Wuhan Province, China.
In Indonesia, the first case of COVID-19 was recorded on March 2, 2020, where two Indonesian citizens (a 31-year-old woman and a 64-year-old mother) tested positive for COVID-19 after making contact with Japanese nationals who came to Indonesia.This fact was found in Indonesian.The availability of the Phobia COVID-19 scale in the Indonesian version that meets the standards is expected to help users identify the level of specific psychological disorders (phobia) related to COVID-19.
Based on the previous description, this study aims to develop and adapt the Indonesian version of the Phobia scale against COVID-19.This research is also expected to provide empirical evidence of the results of language translation, psychometric validation and the development of the Indonesian version of the COVID-19 Phobia Scale (C19P-S).

Method
This study uses a quantitative approach and was carried out in September 2020 -January 2021.The translation procedure begins with a study of the latest literature related to phobia to COVID-19.Furthermore, the adaptation process of this scale involves one psychometric expert to weigh the instrument content qualitatively, and an Indonesian expert for the linguistic aspects used.Weighing the scale is done quantitatively with a limited field trial mechanism.Testing of the instrument in the Indonesian version was carried out on a limited basis and continued more broadly as the sample group was targeted in this study.
Data collection and instrument deployment are carried out with the help of Google Form.Furthermore, the data collection process also involved several volunteers assigned to designated area points to ensure data distribution was spread out and represented the needs of the research being carried out.Before collecting data, the respondents were given information and an introduction from the research team.There is no compulsion for respondents to participate in this research, and; all personal information of respondents is credential.
The COVID-19 Phobia Scale (C19P-S) developed by Arpaci et al. (2020) is the scale used in the translation and validation process in this study.C19P-S contains 20 items covering respondent responses regarding the presence or absence of disorders (1) Psychological, (2) Psycho-somatic, (3) Economic, and (4) Social.
Study conducted by Arpaci et al. (2020) shows that shows that C19P-S has good evidence of construct validity, convergent, discriminant, and internal consistency reliability.The C19P-S is a self-report instrument with fve-point Likert-type scale to assess the levels of coronavirus (COVID-19) phobia.All items are rated on a 5-point scale from "strongly disagree (1)" to "strongly agree (5)." This study involved 220 respondents who were taken randomly and came from several regions in Indonesia.We mapped them into certain demographic aspects, such as age, gender, area of origin, exercise routine in one week, and experience of carrying out a Covid-19 test.The distribution of demographic aspects of the participants is presented in Table 1.The initial stage of data analysis was carried out by scanning with the aim of seeing the quality of the data that had been collected.The quality of research data is determined by how big the respondents are outliers.Furthermore, the main analysis of this study was carried out with the Rasch modeling to provide an estimate of the psychometric properties of the Indonesian version of the COVID-19 Phobia Scale which includes (1) item and person reliability; (2) unidimensionality and rating scale analysis; (3) items and person difficulties; (4) biases item based on differential items functioning.

Result and Discussions
There is a large part of which is the subject of the validation process for the Indonesian version of the C19P-S.

Initial Screening
In this section we conduct an investigation to see the quality of the data that has been collected.The aim is to check the pattern of responses given by respondents to the C19P-S items that have been given, and also the appropriateness of the items.In the Rasch Model, the accuracy of the data collected and the suitability of the data to the ideal model are in the Outfit value range of 0.5 -1.5 logit, where items and persons who have values outside that range can be detected as outliers (Sumintono & Widhiarso, 2014).The results showed that out of 220 respondents who filled in C19P-S, there were 100 respondents who gave inappropriate responses (outliers).
This empirical fact shows us that almost 50% of respondents tend to give "wrong" responses than they should.This also prompted us to use only 120 respondents and 19 C19P-S items for further analysis.

Reliabilities Item and Person
The C19P-S computation (N = 120, I = 19) shows that the reliability value of C19P-S for items (.99) and persons (.90) is in the very high category, with ɑ Cronbach = .90.This shows that the items used in C19P-S have the ability to accurately define latent traits, namely Covid-19 phobia.Likewise, the reliability of the person indicates that there is consistency in the response pattern given by all respondents who fill in the C19P-S.
Another important finding that is also presented in this section is that the Separation Index value is able to classify the ability of respondents into three clusters (3.07) and 8 clusters (8.82) for C19P-S items.This indicates that both persons or items can properly map the conditions and levels of phobia experienced by the respondents with Covid-19.

Unidimensionality and Rating Scale Analysis
Unidimensionality test on C19P-S aims to evaluate whether the instrument which has developed are able to measure the measureable thing such as Phobia Covid-19.Table 2 shows that Raw Variance Explained by Measures as 60,6%, means that Unidimensionality condition of C19P-S is sufficient.On the other hand, C19P-S can be used to measure the scale of Phobia Covid-19.Furthermore, the results of the rating scale analysis test show that the alternative answers offered in the Indonesian version of C19P-S are good and do not cause specific confusion for the respondents.Appendix I shows that empirically, there is an increase in the dynamic andrich threshold value.

Items and Persons Difficulties
In this section we test the difficulty level of items and people.Items difficulties aim to evaluate the level of items from the most difficult to the easiest.Table 3 shows that Item No. 8 "Kekhawatiran saya terhadap virus corona membuat saya sulit bernafas" (+2.18 logit) is the item most difficult to agree on by all respondents who filled out C19P-S.Instead, Item No. 2 "Saya cemas jika ada keluarga dekat saya terinfeksi virus corona" (-1.80 logit).

Differential Items Functioning (DIF)
Another important point of this study is to evaluate whether the items in the C19P-S are biased towards certain demographic groups.We include six demographic aspects in this study, namely (1) Gender, (2) Age, (3) Domicile, (4) Marital Status, (5) Sports Exercise Per Week, and; (6) Experiences on Covid-19 Test.Differential Items Functioning (DIF) item is identified if Prob.<.05.DIF analysis on the demographic aspects of the C19P-S 01 results there is no.That is, the potential DIF of the item is not identified.However, the sports exercise per week in point number 10, shows a DIF .0151.
Table 4 shows that of the 6 demographic aspects, item No. 10 "Saya mengalami gangguan tidur karena kondisi pandemik virus corona" which is biased towards one particular demographic aspect, namely Sports Exercise Per Week.Table 4 in detail shows that the phobic response pattern to Covid-19 does not work well with the respondents' length of exercise.Table 4, the group of respondents who had sports activities once and more than three times a week gave different responses (bias).This indicates that Item No. 10 in the Indonesian version of the C19P-S does not work well for both groups of respondents.
After going through the initial screening, reliabilities item and person, unidimensionality and rating scale analysis, items and persons difficulties, & Differential Items Functioning (DIF), the COVID-19 Phobia Scale (C19P-S) can be used among the general public.Further researcher's suggestion is to be able to use this COVID-19 Phobia Scale (C19P-S) for applied research.

Table 3 .
Mapping the difficulty level of C19P-S items (N = 120, I = 19) Kekhawatiran saya terhadap virus corona membuat saya sulit bernafas EN = My concern about the corona virus makes it difficult for me to breathe ID = Saya mengalami gangguan tidur karena kondisi pandemik virus corona Saya merasa tidak nyaman dengan berita kematian akibat virus corona EN = I feel uncomfortable with the news of the death from the corona virus ID = Saya takut terinfeksi virus corona EN = I am afraid of being infected with the corona virus ID = Dalam situasi pandemi virus corona, saya lebih memperhatikan kebersihan tangan saya jauh dari biasanya.EN = In the coronavirus pandemic situation, I pay more attention to my hand hygiene than usual.ID = Saya cemas jika ada keluarga dekat saya terinfeksi virus corona EN = I am worried if my close family is infected with the corona virus , in the evaluation of persons abilities, it is known that Person No. 100 (100 M B PB UM B Never) is the person who has the highest level of phobia towards Covid-19 (+5.88 logit) when compared to other respondents.Instead, Person No. 84 (84 UM E Yes RT Antigen) is the person with the lowest phobia level towards Covid-19 (-1.04 logit).Information regarding the persons abilities distribution is presented in full in Appendix II of this article.
ID = Pandemi virus corona membuat saya mudah cemas ketika melihat orang lain batuk.EN = The coronavirus pandemic makes it easy for me to worry when I see other people coughing.ID = Aktivitas fisik yang biasanya mudah saya lakukan menjadi sulit ketika pandemi virus corona melanda lingkungan saya.EN = The physical activity that I usually do easily becomes difficult when the corona virus pandemic hits my neighborhood.ID = Saya kuatir pandemi virus corona yang terus berlangsung akan mengakibatkan krisis bahan makanan EN = I am worried that the ongoing corona virus pandemic will result in a food crisis ID = Dalam periode pandemi virus corona, sulit bagi saya untuk merasa rileks jika jarak (fisik) saya dengan orang lain terlalu dekat EN = In the pandemic period of the coronavirus, it is difficult for me to relax if my (physical) distance from other people is too close ID = Penyebaran virus corona yang begitu cepat membuat saya panik EN = The spread of the corona virus so fast makes me panic ID = Sedapat mungkin saya berupaya menghindari orang yang saya lihat mengalami bersin-bersin.Meanwhile

Table 4 .
DIF details on Sports Exercise Per Week (N=120, Item Number 10)