# Efficient Machine Learning Models for Early Stage Detection of Autism Spectrum Disorder
## 3 Methodology
### Data Preprocessing
\begin{table}
\begin{tabular}{l l l} \hline \hline
**Feature** & **Type** & **Description** \\ \hline Age (Year) & Number & Toddlers (months), children, adolescent, and adults (year) \\ Gender & String & Male or female \\ Ethnicity & String & List of common ethnicities \\ Born with jaundice & Boolean & Whether the case was born with jaundice \\ Family member with PDD & Boolean & Whether any immediate family member has a PDD history \\ Who is completing the test & String & Parent, self, caregiver, medical staff, clinician, etc. \\ Country of residence & String & List of countries \\ Used the screening app before & Boolean & Whether the user has formerly used the screening app \\ Language & String & The user’s language details \\ \multirow{2}{*}{A1: Answer of Q1} & \multirow{2}{*}{Binary(0,1)} & Does your child look at you when you call his/her name? (Toddler) \\  & & S/he often notices small sounds when others do not. (Child) S/he \\  & &notices patterns in things all the time. (Adolescent) I often notice \\  & & small sounds when others do not. (Adult) \\ A2: Answer of Q2 & Binary(0,1) & How easy is it for you to get eye contact with your child? (Toddler) \\  & & S/he usually concentrates more on the whole picture rather than the \\  & & small details. (Child, adolescent, adult) \\  & & Does your child point to indicate that s/he wants something? (Toddler) \\ A3: Answer of Q3 & Binary(0,1) & In a social group, s/he can easily keep track of \\  & & several different people’s conversations. (Adolescent) I find it easy to \\  & & do more than one thing at once. (Adult) \\  & & Does your child point to share interest with you? (Toddler) S/he finds \\ A4: Answer of Q4 & Binary(0,1) & it easy to go back and forth between different activities. (Child) If there \\  & & is an interruption, s/he can switch back to what s/he was doing very quickly. (Adolescent) If there is an interruption, I can switch back to \\  & & what I was doing very quickly (Adult) \\ A5: Answer of Q5 & Binary(0,1) & Does your child pretend? (Toddler) S/he does not know how to keep a conversation going with his/her peers. (Child, Adolescent) I find it easy to \"read between the lines\" when someone is talking to me. (Adult) \\  & & Does your child follow where you are looking? (Toddler) S/he is good \\  & at social chit-chat (Child, Adolescent). I know how to tell if someone \\  & & listening to me is getting bored (Adult) \\  & & If you or someone else in the family is visibly upset, does your child \\  & & show signs of wanting to comfort them? (Toddler) When s/he is read \\  & a story, s/he finds it difficult to work out the character’s intentions or \\  & feelings (Child). When s/he was younger, s/he used to enjoy playing \\  & games involving pretending with other children (Adolescent). When \\  & I am reading a story I find it difficult to work out the characters’ \\  & & intentions (Adult). \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Features description. **Data Cleaning:** We cleaned these datasets to simplify this model and increased classification accuracy by deleting instances with missing values. After that, we discarded some irrelevant features (i.e., those which are not related to ASD) such as the case, whether they the used app before, the user (who completed the screening), the language, why they had taken the screening, the age description, the screening type, and the score, respectively. The score 7 to 10 was used to classify ASD prediction for the child, adolescent, and adult datasets. A value of 4 or higher was classified as ASD for the toddler dataset. In this work, we selected 16 features for the child, adolescent, and adult datasets and 15 features for the toddler dataset, respectively.