Making its debut on 12/13/2016, smart beta exchange traded fund Nuveen ESG MidCap Growth ETF (NUMG) provides investors broad exposure to the Style Box - Mid Cap Growth category of the market.What Are Smart Beta ETFs?Market cap weighted indexes were created to reflect the market, or a specific segment of the market, and the ETF industry has traditionally been dominated by products based on this strategy.A good option for investors who believe in market efficiency, market cap weighted indexes offer a low-cost, convenient, and transparent way of replicating market returns.On the other hand, some investors who believe that it is possible to beat the market by superior stock selection opt to invest in another class of funds that track non-cap weighted strategies--popularly known as smart beta.Non-cap weighted indexes try to choose stocks that have a better chance of risk-return performance, which is based on specific fundamental characteristics, or a mix of other such characteristics.This area offers many different investment choices, such as simplest equal-weighting, fundamental weighting and volatility/momentum based weighting methodologies; however, not all of these strategies can deliver superior results.Fund Sponsor & IndexManaged by Nuveen, NUMG has amassed assets over $341.05 million, making it one of the average sized ETFs in the Style Box - Mid Cap Growth. Before fees and expenses, NUMG seeks to match the performance of the TIAA ESG USA Mid-Cap Growth Index.The TIAA ESG USA Mid-Cap Growth Index comprises of equity securities issued by mid- capitalization companies listed on US exchanges. It uses a rules-based methodology that provides investment exposure that generally replicates that of mid-cap growth benchmarks through a portfolio of securities that adhere to predetermined ESG, controversial business involvement and low-carbon screening criteria.Cost & Other ExpensesSince cheaper funds tend to produce better results than more expensive funds, assuming all other factors remain equal, it is important for investors to pay attention to an ETF's expense ratio.Operating expenses on an annual basis are 0.30% for NUMG, making it on par with most peer products in the space.The fund has a 12-month trailing dividend yield of 0%.Sector Exposure and Top HoldingsETFs offer diversified exposure and thus minimize single stock risk, but it is still important to delve into a fund's holdings before investing. Most ETFs are very transparent products and many disclose their holdings on a daily basis.NUMG's heaviest allocation is in the Information Technology sector, which is about 34% of the portfolio. Its Healthcare and Industrials round out the top three.Taking into account individual holdings, Cadence Design Sys Inc (CDNS) accounts for about 3.66% of the fund's total assets, followed by Mettler-Toledo International (MTD) and Insulet Corp (PODD).Its top 10 holdings account for approximately 26.12% of NUMG's total assets under management.Performance and RiskThe ETF has lost about -26.24% so far this year and is down about -25.88% in the last one year (as of 11/24/2022). In the past 52-week period, it has traded between $32.21 and $57.14.NUMG has a beta of 1.10 and standard deviation of 28.43% for the trailing three-year period. With about 70 holdings, it effectively diversifies company-specific risk.AlternativesNuveen ESG MidCap Growth ETF is a reasonable option for investors seeking to outperform the Style Box - Mid Cap Growth segment of the market. However, there are other ETFs in the space which investors could consider.IShares ESG Aware MSCI EAFE ETF (ESGD) tracks MSCI EAFE ESG Focus Index and the iShares ESG Aware MSCI USA ETF (ESGU) tracks MSCI USA ESG Focus Index. IShares ESG Aware MSCI EAFE ETF has $6.83 billion in assets, iShares ESG Aware MSCI USA ETF has $20.64 billion. ESGD has an expense ratio of 0.20% and ESGU charges 0.15%.Investors looking for cheaper and lower-risk options should consider traditional market cap weighted ETFs that aim to match the returns of the Style Box - Mid Cap Growth.Bottom LineTo learn more about this product and other ETFs, screen for products that match your investment objectives and read articles on latest developments in the ETF investing universe, please visit Zacks ETF Center. Want key ETF info delivered straight to your inbox? Zacks’ free Fund Newsletter will brief you on top news and analysis, as well as top-performing ETFs, each week.Get it free >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Nuveen ESG MidCap Growth ETF (NUMG): ETF Research Reports Cadence Design Systems, Inc. (CDNS): Free Stock Analysis Report Insulet Corporation (PODD): Free Stock Analysis Report MettlerToledo International, Inc. (MTD): Free Stock Analysis Report iShares ESG Aware MSCI EAFE ETF (ESGD): ETF Research Reports iShares ESG Aware MSCI USA ETF (ESGU): ETF Research ReportsTo read this article on Zacks.com click here.Zacks Investment Research