Participants in the intervention arm received a structured therapeutic story reading intervention during their hospitalization in the pediatric ward. The intervention was implemented on three consecutive days during the child's inpatient stay, at a time that did not interfere with medical treatment or nursing care, and was conducted in the child's hospital room.

One therapeutic storybook was read per day (three books in total). The intervention was primarily delivered by a pediatric nursing specialist researcher.

Three therapeutic storybooks specifically selected to positively influence the hospitalization experience were used:

"I Have a Fever" - aimed at helping children understand fever and related nursing interventions.

"From A to Z: Hospital (Interactive Alphabet)" - aimed at familiarizing children with hospital equipment and healthcare professionals.

"Sometimes It Happens: I Guess I Felt a Little" - aimed at helping children recognize and express fear related to hospitalization.

Participants in the routine care arm received routine pediatric ward care without therapeutic story reading sessions.

The intervention consists of a structured, developmentally appropriate therapeutic story reading program designed specifically for hospitalized preschool children (4-6 years of age). The program is implemented individually in the child's hospital room over three consecutive days, with one therapeutic storybook read per day. The distinguishing features of this intervention are: (1)its structured and sequential delivery during hospitalization, (2)the use of carefully selected therapeutic storybooks targeting fear of nursing interventions, hospital equipment, and emotional expression, and (3)its implementation under the supervision of a pediatric nursing specialist to ensure consistency and therapeutic intent. Unlike routine care, the intervention systematically addresses children's hospitalization-related fears and emotional responses. The content of the selected books is developmentally appropriate and suitable for helping children understand medical procedures (e.g., fever management).

Fear levels are assessed using the Fear of Children Against Nursing Interventions and Used Materials Scale (FCANIM), a 18-item instrument developed to evaluate children's fear of nursing procedures and commonly used medical materials. The scale consists of two subdimensions: (1) fear of frequently encountered materials and (2) fear of less frequently encountered materials. Each item includes a visual representation of a nursing intervention or medical material (e.g., stethoscope, thermometer). Children rate their level of fear for each image using a five-point Likert-type scale illustrated with facial expressions representing increasing levels of fear. Total scores range from 18 to 90. Higher scores indicate higher levels of fear toward nursing interventions and medical materials, while lower scores indicate lower fear levels. The internal consistency of the scale is high, with Cronbach's alpha coefficients ranging from 0.89 to 0.93 for the subdimensions and 0.94 for the total scale.

Problematic media use is assessed using the 9-item Problematic Media Use Scale - Short Form (PMUS-SF). The scale evaluates problematic use of screen-based media devices, including television, computers, tablets, and smartphones.

Items are rated on a 5-point Likert scale based on the frequency of screen-use behaviors. The total score is calculated by summing the item scores and dividing by nine. Final scores range from 1 to 5. Higher scores indicate higher levels of problematic media use, whereas lower scores indicate lower levels of problematic media use. The original scale demonstrated high internal consistency (Cronbach's alpha = 0.92). In the present study, Cronbach's alpha was 0.78 at pre-test and 0.80 at post-test.

Parental stress is assessed using the 16-item Parental Stress Scale (PSS). The scale consists of four subdimensions: parental stressors, loss of control, satisfaction, and rewards. Items are rated on a 5-point Likert-type scale. Total scores range from 16 to 80. Higher scores indicate higher levels of parental stress, whereas lower scores indicate lower levels of parental stress. In the Turkish validation study, Cronbach's alpha coefficients for the subscales ranged between 0.70 and 0.76, and 0.81 for the total scale score. In the present study, Cronbach's alpha was 0.73 at pre-test and 0.76 at post-test.