The Likert-type format is one of the most widely used in all types of scales in the field of social sciences. Nevertheless, there is no definitive agreement on the number of response categories that optimizes the psychometric properties of the scales. The aim of the present work is to determine in a systematic fashion the number of response alternatives that maximizes the fundamental psychometric properties of a scale: reliability and validity. The study is carried out with data simulated using the Monte Carlo method. We simulate responses to 30 items with correlations between them ranging from 0.2 to 0.9. We also manipulate sample size, analyzing four different sizes: 50, 100, 200, and 500 cases. The number of response options employed ranges from two to nine. The results show that as the number of response alternatives increases, both reliability and validity improve. The optimum number of alternatives is between four and seven. With fewer than four alternatives the reliability and validity decrease, and from seven alternatives onwards psychometric properties of the scale scarcely increase further. Some applied implications of the results are discussed.

When one-way ANOVA is statistically significant, a multiple comparison problem arises, hence post-hoc tests are needed to elucidate between which groups significant differences are found. Different post-hoc tests have been proposed for each situation regarding heteroscedasticity and sample size groups. This study aims to compare the Type I error (α) rate of 10 post-hoc tests in four different conditions based on heteroscedasticity and balance between-group sample size. A Montecarlo simulation study was carried out on a total of 28 data sets, with 10,000 resamples in each, distributed through four conditions. One-way ANOVA tests and post-hoc tests were conducted to estimate the α rate at a 95% confidence level. The percentage of times the null hypothesis was falsely refused is used to compare the tests. Three out of four conditions demonstrated considerable variability among sample sizes. However, the best post-hoc test in the second condition (heteroscedastic and balance group) did not depend on simple size. In some cases, inappropriate post-hoc tests were more accurate. Homoscedasticity and balance between-group sample size should be considered for appropriate post-hoc test selection.

Schizotypy is a multidimensional personality construct that appears to indicate psychosis proneness. Supposedly, schizotypal traits behave differently depending on a person's age and gender, but few studies have examined this relationship. In our study we used the Thinking and Perceptual Style Questionnaire and the Junior Schizotypy Scales. The sample was made up of 321 students (169 males) with an age range of 12 to 17 years. The results show significant differences in gender and age groups. Males score higher than females on Physical Anhedonia, Social Anhedonia, and Impulsive Non-Conformity scales, while females score higher or Positive Symptoms, Negative Evaluation, and Social Paranoia scales. Significant differences were also found among age groups: Unusual experiences, self-referent ideation, social paranoia, thought disorder, and negative evaluation were more frequent in later stages of adolescence. However, the meaning of this difference could be interpreted in terms of emotional turbulence rather than as a direct indicator of vulnerability to psychosis.

Attentional and working memory (WM) processes undergo significant changes during different stages of development. However, currently there are not many continuous performance tools based on virtual reality (VR) for measuring attentional capacity in adults. The present study aimed to obtain normative data for the Nesplora Aquarium VR test in a Spanish population, looking at sex and age variables. In addition, this study also aimed to analyze the psychometric properties of the tool such as scale, internal consistency, and item difficulty and discrimination indices. A total of 1,469 participants from different regions of Spain (57.6% female) with ages ranging from 16 to 90 years old took part in this normative study. Nesplora Aquarium was developed in order to support clinicians in the assessment of attentional processes and WM in adults over 16 years old. It is an 18-minute individual test performed through a VR system. The system provides better visual and auditory immersion in the task than computerized CPTs. This study revealed that the new VR tool, designed to measure adult attention and working memory levels, exhibited good psychometric properties related to reliability and internal consistency. In addition, item difficulty and discrimination values were also acceptable.

Grit is one of the non-cognitive variables that has received the most attention in recent years given its relationship to and influence in various aspects of life. There are very few reliable, valid instruments to evaluate it in Spanish-speaking countries. Because of that, the aim of this study is the development and validation of a new scale to evaluate grit in Spanish-speaking contexts. We used a sample of 531 Spanish participants (60% women) from the general population (M_years = 38.60, SD_years = 14.90). We examined the structure and measurement invariance of the instrument. We calculated the instrument’s reliability and obtained evidence of validity in relation to other variables. We examined the differences in grit as a function of gender and age. The factorial analyses confirmed the unidimensionality of the instrument, along with the measurement invariance of the scores with respect to sex and age. The new grit scale demonstrated excellent reliability (α = .94; ω = .94). We found clear evidence of validity in relation to other variables; the Grit short scale (r = .691), self-control (r = .595), self-efficacy (r = .703), and conscientiousness (r = .661). The new scale for evaluating grit (Oviedo Grit Scale) is essentially unidimensional, and scores produced by it exhibit excellent indicators of reliability and validity.

Likert items are often used in social and health sciences. However, the format is strongly affected by acquiescence and reversed items have traditionally been used to control this response bias, a controversial practice. This paper aims to examine how reversed items affect the psychometric properties of a scale. Different versions of the Grit-s scale were applied to an adult sample (N = 1,419). The versions of the scale had either all items in positive or negative forms, or a mix of positive and negative items. The psychometric properties of the different versions (item analysis, dimensionality and reliability) were analyzed. Both negative and positive versions demonstrated better functioning than mixed versions. However, the mean total scores did not vary, which is an example of how similar means could mask other significant differences. Therefore, we advise against using mixed scales, and consider the use of positive or negative versions preferable.